Heat exchange reactor with reduced metal dusting

Abstract

The present technology relates to a heat exchanging reactor (HER) system comprising a first gas feed and a heat exchanging reactor, HER. The HER has two reaction zones; a first reaction zone (I) arranged to perform an overall exothermic reaction on the first gas feed and a second reaction zone (II) arranged to perform an overall endothermic reaction on the gas from said first reaction zone (I).

Description

Technical Field

[0001] This technology relates to a method for converting a first gas feed containing CO2 and H2 into a synthesis gas (syngas) stream via a CO2 shift reaction in a heat exchange reactor (HER). The HER has two reaction zones: a first reaction zone arranged to perform an overall exothermic reaction on the first gas feed and a second reaction zone arranged to perform an overall endothermic reaction on the gas from the first reaction zone (I). Background Technology

[0002] According to the following reaction, the production of CO from CO2 can be carried out via a reverse water-gas shift reaction:

[0003]

[0004] This is an endothermic reaction, therefore requiring an energy input to proceed. This technology has rarely been industrially implemented in practice, but theoretically, a configuration similar to a steam methane reformer (SMR) where heat is supplied externally could favor the reaction, and heated reactor zones or reactor tubes would also be beneficial.

[0005] However, external heating typically involves the combustion of hydrocarbon fuels, thus usually generating associated CO2 emissions, which contradicts the current interests of the chemical industry, which has focused on reducing greenhouse gas emissions in recent years. In principle, external heating could also be provided through hydrogen combustion, where hydrogen is supplied via electrolysis. However, this route would require a significant amount of electricity to produce hydrogen, making this option expensive and not preferred.

[0006] This technology aims to provide an efficient heat exchange reactor (HER) and a method for producing CO from CO2. In particular, this technology reduces or completely avoids, where possible, the risk of metal dust formation on both the process and heating sides. Summary of the Invention

[0007] It has been found that the method presented in this paper for CO2 conversion and the HER reactor offers a much lower risk of metal dust formation compared to heat exchange steam methane reformers.

[0008] This invention is as defined in the independent claims.

[0009] In one embodiment, a method is provided for converting a first gas feed containing CO2 and H2 into a synthesis gas stream via a CO2 shift reaction of the first gas feed in a heat exchange reactor (HER), wherein the HER comprises:

[0010] At least one process side and at least one heating side, wherein the process side of the HER includes a process side inlet and a process side outlet.

[0011] The process side of HER includes a first reaction zone (I) located closest to the process side inlet.

[0012] Furthermore, the process side of HER includes a second reaction zone (II) located closest to the process side outlet.

[0013] The heating side of HER includes a heating side inlet and an optional heating side outlet.

[0014] The at least one process side and the at least one heating side are arranged such that heat transfer from the heating side to at least a portion of the process side is possible.

[0015] The method includes the following steps:

[0016] - A first gas feed is supplied to the process side of HER via the process-side inlet;

[0017] - Heating fluid is supplied to the heating side of the HER via the heating side inlet, and heat transfer from the heating fluid to the process side of the HER is allowed;

[0018] - The overall exothermic reaction of the first gas feed is carried out in the first reaction zone (I), wherein the overall exothermic reaction includes at least the following reactions, which have a net progression from left to right:

[0019]

[0020]

[0021] - An overall endothermic reaction of the gas from the first reaction zone is carried out in the second reaction zone (II), wherein the overall endothermic reaction includes at least the following reactions, which have a net progression from left to right:

[0022]

[0023]

[0024] -A synthetic gas stream, optionally mixed with cooled fluid, is discharged from the process side via a process-side outlet;

[0025] and

[0026] - Optionally, the cooled fluid is discharged from the heating side via a heating side outlet.

[0027] A heat exchange reactor (HER) for carrying out this process is also provided. Further details of this technology are provided in the following description, drawings and dependent claims.

[0028] Brief description of the attached figures

[0029] The technology is described with reference to the attached schematic diagram, wherein:

[0030] Figure 1 A heat exchange reactor (HER) system according to the present invention is shown.

[0031] Figure 2 It showed something similar to Figure 1 The HER system is a bayonet-type HER reactor.

[0032] Figure 3 The system according to the invention is shown, which includes an electro-reverse water-gas shift (e-RWGS) reactor and a heat exchange reactor (HER).

[0033] Figure 4 It showed something similar to Figure 3 The system in which the first and second feeds originate from a common feed.

[0034] Figure 5 It showed something similar to Figure 5 The system, in which HER has two independent heating sides.

[0035] Figure 6 A system further comprising a combustion unit according to the present invention is shown.

[0036] Figure 7 It showed something similar to Figure 6 The system in which the first and second feeds originate from a common feed.

[0037] Figure 7A A system according to the invention is shown, wherein a flash separation unit is provided to remove condensate.

[0038] Figure 7B It showed something similar to Figure 7A The system.

[0039] Figure 8-10 The temperature of the gas and the actual gas carbon activity curves in the HER heating side of Examples 4, 5 and 6 are shown.

[0040] Figure 11 An alternative arrangement of the HER of the present invention is shown, wherein the synthesis gas flow and the cooling fluid are combined before the HER outlet. Invention Details

[0042] Unless otherwise stated, any given percentage of gas content is a percentage by volume.

[0043] The system may also include any additional units and connections (e.g., pipes) that a person skilled in the art may deem necessary.

[0044] When heating and subsequent cooling are performed using a CO-containing gas, carbon formation due to the so-called metal dusting phenomenon must be considered. The central carbon-forming reactions to consider are the Boudouard reaction and the CO reduction reaction described herein. Both of these reactions are exothermic, and therefore prefer to proceed at lower temperatures.

[0045] One measure to assess the risk of carbon formation is carbon activity (a C According to the following:

[0046] a c =K eq (CO red)*p(CO)*p(H2) / p(H2O)

[0047] Where K eq (CO red) is the thermodynamic equilibrium constant for the CO reduction reaction, and p(i) is the partial pressure of i. Note that when a C When the a value is less than 1, carbon formation cannot occur. c The temperature at which the carbon monoxide concentration equals 1 is called the carbon monoxide reduction temperature (T). CO ).

[0048] The Boudouard reaction can be expressed similarly. The Boudouard reaction's a... c The temperature equal to 1 is called the Boudouard temperature (T). B ).

[0049] In a first embodiment, a method is provided to convert a first gas feed containing CO2 and H2 into a synthesis gas (syngas) stream through a CO2 shift reaction of a first gas feed in a specific heat exchange reactor (HER).

[0050] heat exchange reactor

[0051] The heat exchanger (HER) is configured to supply heat to the endothermic reaction using hot gas through heat exchange, typically on the tube walls. One example of a heat exchanger configuration has several parallel tubes filled with a typical granular catalyst that receives the feed gas. At the bottom of the reactor, product gas from the catalyst-filled tubes mixes with hot syngas from the upstream reforming unit, and the combined syngas exchange heat with the catalyst-filled tubes. Other configurations of heat exchanger reactors are also conceivable.

[0052] In a preferred embodiment, the catalyst for HER is a non-selective catalyst. Examples of such catalysts include noble metals on Ni / MgAl2O4, Ni / Al2O3, Ni / CaAl2O4, NiIr / MgAl2O4, Ni / ZrO2, Ru / MgAl2O4, Rh / MgAl2O4, Ir / MgAl2O4, Ru / ZrO2, NiIr / ZrO2, Mo2C, Wo2C, CeO2, and Al2O3. Other examples include active metals on various forms of calcium aluminate, such as nickel, iridium, rhodium, and / or ruthenium.

[0053] The HER has at least one process side and at least one heating side. The process side of the HER includes a process side inlet and a process side outlet, while the heating side of the HER includes a heating side inlet and an optional heating side outlet. The respective inlets and outlets are fluidly connected within each side of the HER.

[0054] The process side and the heating side are separated from each other by an inner wall, allowing heat transfer from the heating side to the process side to occur. In one aspect, the HER may include two heating sides.

[0055] The process side of the HER is the side where the CO2 shift reaction occurs. The process side of the HER may include one or more catalysts that promote the CO2 shift reaction. The catalysts also catalyze methanation and steam reforming reactions, as described below. The catalysts used in both reaction zones are suitably non-selective.

[0056] The heating side of HER is not designed for chemical reactions to occur; instead, thermal energy from the hot fluid passing through the heating side is transferred to the process side.

[0057] A HER can be a typical "shell-and-tube" heat exchange reactor, consisting of multiple catalyst-packed tubes located within a shell. There are fluid connections between the interiors of all the tubes, but no fluid connection between the interior and exterior of the tubes. In operation, one fluid flows through the interior of the tubes, while a second fluid flows in the shell outside the tubes. Heat is transferred from one fluid to the other through the tube walls. A manifold arrangement is located at each end of the tube bundle.

[0058] HERs will typically operate at pressures close to any associated reactor, in one respect, an RWGS reactor, such as an e-RWGS.

[0059] As described above, the process side of the HER includes a process-side inlet (through which the first gas feed enters the HER) and a process-side outlet (through which the synthesis gas exits the HER). The first reaction zone (I) is located closest to the process-side inlet, and the second reaction zone (II) is located closest to the process-side outlet. The term "located closest to" should be measured according to the gas path, not a geometric measurement.

[0060] The first reaction zone (I) is arranged for an overall exothermic reaction to carry out the first gas feed.

[0061]

[0062]

[0063] Both of these reactions occur in the first reaction zone (I).

[0064] The second reaction zone (II) is arranged to conduct a total endothermic reaction on the gas from the first reaction zone (I). The main reactions occurring in this zone are:

[0065]

[0066]

[0067] Typically, the RWGS / water-gas shift reaction and the steam reforming / methanation reaction are at or near chemical equilibrium at the HER outlet.

[0068] In one aspect, the process side of the HER has a total length extending from the process side inlet to the process side outlet, and wherein the first reaction zone (I) has an extension of less than 50%, for example less than 30%, preferably less than 20%, more preferably less than 10% of the total length of the HER process side. The first catalyst may be located at least in the first reaction zone (I) and may extend at least partially into the second reaction zone (II).

[0069] In another embodiment, the same type of non-selective catalyst is used in both the first and second reaction zones. The non-selective catalyst catalyzes both reactions (1) and (2). The non-selective catalyst can also catalyze other reactions, such as steam reforming of higher hydrocarbons like ethane and propane.

[0070] Properly, at least the end of the first reaction zone (I) located closest to the process-side inlet of the HER is not in direct contact with the heating side of the HER, such that this end of the first reaction zone (I) is primarily heated by the adiabatic temperature rise caused by the exothermic reaction. The process-side inlet of the HER is the end of the HER into which the first gas feed enters.

[0071] In HER reactors, carbon formation on the catalyst must be avoided. Furthermore, it is well known that when gases including CO are generated, especially when cooling such gases, there is a risk of metal dust formation. This invention avoids or significantly reduces the risks of carbon formation and metal dust formation in HER reactors.

[0072] Metal dusting can occur on metal walls in the presence of gases including CO. The chemical reactions that typically lead to metal dusting are one of the following:

[0073]

[0074]

[0075] The first reaction is called the Boudouard reaction, and the second reaction is called the CO reduction reaction. In severe cases, metal dusting can lead to rapid degradation of the metal walls and cause serious equipment failure.

[0076] As a central part of this invention, the use of a non-selective catalyst is preferred over the use of a selective catalyst, for the following reasons:

[0077] When a non-selective catalyst is used in the first reaction zone (I), methanation occurs in addition to the RWGS reaction. This results in the release of chemical energy to heat the system, and a temperature rise due to the exothermic nature of methanation. Since CO reduction is also exothermic, the temperature rise from methanation reduces the potential for CO reduction, and at a certain temperature level, there is no potential for CO reduction to occur at all. This precise level will depend on the specific reactant concentration, inlet temperature, and pressure, but is typically in the range of 500–800 °C; above this temperature range, CO reduction will not occur. Note that the exothermic reaction from methanation will produce the highest temperature rise at the catalyst active sites on the structured catalyst surface, where carbon formation can occur. Therefore, this exothermic effect has a significant positive impact on reducing the carbon formation potential on the catalyst.

[0078] In summary, this HER configuration allows for the promotion of reverse water-gas shift and methanation reactions within the HER without the side reaction of carbon formation on the catalyst or metal surface, as methanation mitigates this, contrary to intuition. The specific configuration of the HER allows for temperatures to be raised from relatively low inlet temperatures to very high product gas temperatures, greater than 500°C, preferably greater than 800°C, and even more preferably greater than 900°C or 1000°C. This means that the methane produced by the methanation reaction will occur in the first reaction zone (I) of the HER reactor, but when it exceeds approximately 600-800°C, this methane will begin to be converted back to a CO-rich product via reverse methanation. This configuration cleverly allows for the removal of some CO and the generation of some H2O within the catalyst bed in the temperature zone where CO reduction is problematic, but subsequently allows for CO regeneration in a high-temperature zone with low or no carbon potential. Effectively, utilizing the high product gas temperature means that the final syngas product can be delivered at a very low methane concentration, although methane has a peak concentration somewhere along the reaction zone. In one embodiment, the reactor system can operate with little or no methane in the first gas feed and very little methane in the synthesis gas stream, but with a methane concentration inside the reaction zone higher than that in the first gas feed and / or the synthesis gas stream. In some cases, this peak methane concentration inside the reaction zone may be an order of magnitude higher than the inlet and outlet methane concentrations.

[0079] As noted above, the CO concentration and carbon formation potential are low when a non-selective catalyst is used. Assuming the gas in the process side of the HER reactor is in equilibrium with respect to reactions (1) and (2), there is typically no thermodynamic potential for carbon formation via either reaction (4) or (5). If a selective catalyst is used and only reaction (1) occurs (i.e., reaction (2) does not occur), the CO concentration will be significantly higher. In this case, there is typically a thermodynamic potential for carbon formation from reactions (4) and (5), and therefore, the risk of carbon formation is significantly higher.

[0080] First gas feed

[0081] A first gas feed consisting of CO2 and H2 is required. This first feed may be or include combustion products composed of another gas from outside the system. Examples of CO2 sources include flue gas or exhaust gas from a CO2 capture unit (e.g., an amine scrubbing unit), bio-derived CO2, CO2 from a direct air capture unit, and / or CO2 from a cement plant or steel plant. Examples of H2 sources include hydrogen produced by electrolysis (e.g., alkaline or solid oxide electrolysis) or hydrogen produced by steam reforming. The first gas feed is converted into a syngas stream via a CO2 shift reaction in a heat exchange reactor.

[0082] A portion of the first feed and / or heating fluid used in this method may also include recirculated gas from downstream units. One example is the recirculation of exhaust gas (or tail gas) from the Fischer-Tropsch synthesis unit. This tail gas may be pretreated before being used as part or all of the first feed and / or heating fluid. Another example is purge gas from the methanol loop.

[0083] Suitablely, the first feed contains 10-60% CO2, such as, for example, 20-35% CO2, 25-35% CO2. Suitablely, the first feed contains 40-90% H2, such as 50-80% H2, 60-70% H2, or 65-70% hydrogen.

[0084] In the first feed, the ratio of H2 to CO2 can be 1-5, such as, for example, 2-4, 2-3, or 2.2-2.5, or 2.8-3.5, or 2.8-3.2. In another embodiment, the molar ratio of CH4 / CO2 in the first feed is preferably less than 0.5, for example, less than 0.2, and preferably less than 0.1.

[0085] Appropriately, the primary source of hydrogen in the first gas feed is the electrolysis unit.

[0086] A portion of the first feed may further originate from a hydrocarbon-containing stream that has been pre-reformed upstream of the HER reactor according to the following reaction:

[0087] C n H m +nH2O→nCO+(n+1 / 2m)H2 (3)

[0088] The above reactions are usually accompanied by methanation and water-gas shift reaction (the reverse of reaction (1)), producing a mixture mainly composed of CO2, H2, CH4 and steam.

[0089] Examples of hydrocarbon streams are those containing alkanes such as ethane, propane, butane, and / or pentane. For alkanes, m = 2n + 2 in equation (3).

[0090] Another example of a hydrocarbon stream is LPG recycled from a downstream synthesis stage of the system of the present invention, such as from a Fischer-Tropsch synthesis unit or a unit that produces hydrocarbons from methanol.

[0091] The first feed may also include other components such as CH4, N2, Ar, O2, CO, or H2O. Other components are also conceivable, such as other hydrocarbons including ethane, typically in small quantities.

[0092] The first feed appropriately has the following composition (by volume):

[0093] 50-80% H2 (dry)

[0094] 20-50% CO2 (dry)

[0095] In one embodiment, the first feed appropriately has the following alternative composition by volume:

[0096] 50-70% H2

[0097] 20-40% CO2

[0098] 2-10% CH4

[0099] 1-8% H2O

[0100] 0-5% CO

[0101] Other components, such as Ar, N2 and ethane, totaling 0-5%.

[0102] In another embodiment, where the natural gas is pretreated by desulfurization and / or pre-reforming, the carbon from the natural gas accounts for less than 20% of the total carbon in the first feed, preferably less than 10%, and more preferably less than 5%.

[0103] The first gas feed may additionally contain methane, suitably up to 3 mol%, or up to 8 mol%, or up to 12 mol% of methane.

[0104] The first gas feed is supplied to the process side of the HER via the process-side inlet. In a specific embodiment, the temperature of the first gas feed is 250°C to 550°C, preferably 260°C to 450°C, preferably 270°C to 400°C, preferably 280°C to 380°C, preferably 290°C to 370°C, and most preferably 300°C to 360°C.

[0105] Heating fluid

[0106] The system also requires a heating fluid. This heating fluid can be partially or entirely composed of combustion products from another gas outside the system. Suitable heating fluids include CO2 and H2, and can also be a syngas stream.

[0107] The heating fluid is supplied to the heating side of the HER via the heating side inlet, and heat transfer occurs from the heating fluid to the HER process side.

[0108] In one aspect, the heating fluid is provided by an electric RWGS (e-RWGS) reactor, a combustion RWGS reactor, or a self-heating RWGS reactor, preferably an electric RWGS (e-RWGS) reactor.

[0109] In one embodiment, where the heating fluid is a syngas stream, the syngas stream and the cooling fluid can be combined in the HER to provide a third product stream from the process-side outlet. In other words, the syngas leaving the second reaction zone is mixed with the hot heating fluid, and then the mixture is cooled, with the cooled fluid exiting the HER reactor.

[0110] As shown above, the heating fluid can be provided by an electric RWGS (e-RWGS) reactor, a combustion RWGS reactor, or a self-heating RWGS reactor, preferably by an electric RWGS (e-RWGS) reactor.

[0111] In one aspect, the RWGS reactor used for the reverse water-gas shift reaction between CO2 and H2 is an electrically heated reverse water-gas shift (e-RWGS) reactor. The e-RWGS reactor uses resistance heating to perform a more efficient reverse water-gas shift process and significantly reduces or preferably avoids the use of fossil fuels as a heat source. The e-RWGS reactor may include selective or non-selective catalysts. Preferably, the eRWGS reactor includes a non-selective catalyst.

[0112] In one embodiment, the e-RWGS reactor suitably comprises:

[0113] - Arrange a structured catalyst for catalyzing the RWGS reaction, the structured catalyst comprising a macrostructure of a conductive material, the macrostructure supporting a ceramic coating, wherein the ceramic coating supports a catalytically active material (for selective e-RWGS);

[0114] - The structured catalyst comprises a macrostructure of a conductive material that supports a ceramic coating, wherein the ceramic coating supports a non-selective catalytically active material (for non-selective e-RWGS);

[0115] -Optionally includes a top layer of non-selective particulate catalyst,

[0116] - A pressure-resistant shell housing the structured catalyst; the pressure-resistant shell includes an inlet for introducing the feed and an outlet for introducing syngas products; wherein the inlet is positioned such that the feed enters the structured catalyst at a first end, and the syngas products exit the structured catalyst from a second end.

[0117] - A heat insulation layer between the structured catalyst and the pressure-resistant shell; and

[0118] - At least two conductors electrically connected to the structured catalyst and a power supply placed outside the pressure-resistant housing, wherein the power supply is sized to heat at least a portion of the structured catalyst to a temperature of at least 500°C by passing current through the macrostructure of the conductive material; wherein the at least two conductors are connected to the structured catalyst at locations closer to the first end of the structured catalyst than to the second end of the structured catalyst, and wherein the structured catalyst is configured to guide current substantially from one conductor to the second end of the structured catalyst and back to the second of the at least two conductors.

[0119] The pressure chamber is suitably designed for a pressure of 2 to 50 bar. It can also have a design pressure of 50 to 200 bar. The at least two conductors typically pass through the pressure chamber within a fitting, such that the at least two conductors are electrically insulated from the pressure chamber. The pressure chamber may also include one or more inlets located near or connected to at least one fitting to allow cooling gas to flow above, around, near, or inside at least one conductor within the pressure chamber. The gas outlet temperature from the e-RWGS reactor is suitably 900°C or higher, preferably 1000°C or higher, and even more preferably 1100°C or higher.

[0120] The eRWGS reactor can also be of a different design and / or can transfer heat via induction.

[0121] The eRWGS reactor may alternatively include a first heating end and a second end, wherein the feed gas at the first heating end is electrically heated to a high temperature such as 800-1000°C, and the second end includes a (adiabatic) catalyst bed containing selective or non-selective catalysts or combinations of catalysts.

[0122] In one embodiment, the RWGS reactor is a combustion-type RWGS reactor. A combustion-type RWGS reactor can consist of multiple tubes containing catalyst particles placed within a furnace. The tubes are typically quite long, for example 10-13 meters, and generally have relatively small inner diameters, such as 80 mm to 160 mm, to collectively provide a high external exposed surface area, facilitating heat transfer to the catalyst. The catalyst can be selective or non-selective, or a combination thereof. Combustion-type RWGS reactors require fuel gas. A burner placed within the furnace provides the necessary heat for the reaction through the combustion of the fuel gas. Due to mechanical constraints, the available heat flux is typically limited, thus increasing capacity by increasing the number of tubes and the size of the furnace. This type of reactor configuration is frequently used for steam reforming, where more details can be found in the art, for example, in "Synthesis gas production for FT synthesis"; Chapter 4, pp. 258-352, 2004. Other types of combustion-type RWGS reactors are also conceivable.

[0123] In one embodiment, the RWGS reactor is a self-heating RWGS reactor, or more preferably one or more pre-reactors, followed by a downstream self-heating RWGS reactor. The exhaust gas from the first pre-reactor may optionally be cooled and fed to a next pre-reactor where the same reaction occurs. Additional pre-reactors may be used. Pre-reactors are typically adiabatic or heated. The outlet gas from the final pre-reactor is fed to the self-heating RWGS reactor.

[0124] In the pre-reactor, reactions (1) and (2) occur. Typically, the gas composition at the outlet of each pre-reactor and the self-heating RWGS reactor is at or near chemical equilibrium with respect to reactions (1) and (2).

[0125] The main components of a self-heating RWGS reactor are a burner, a combustion chamber, and a catalyst bed contained within a refractory-lined pressure shell. Self-heating RWGS reactors require an oxygen feed. In a self-heating RWGS reactor, the feed is partially combusted with substoichiometric amounts of oxygen followed by water-gas shift reaction, and optionally, the partially combusted gas is steam reformed in a fixed bed of catalyst. Typically, the gas is at or near equilibrium at the reactor outlet relative to the water-gas shift and steam reforming reactions. The outlet gas temperature is typically in the range of 850°C to 1100°C. This type of reactor configuration is frequently used for the production of syngas from hydrocarbon feedstocks, more details of which can be found in the art, for example, in "Studies in Surface Science and Catalysis," Vol. 152, "Synthesis gas production for FT synthesis"; Chapter 4, pp. 258-352, 2004.

[0126] Alternatively, a combustion-type RWGS reactor can be used, followed by a self-heating RWGS reactor. In this case, the effluent from the RWGS reactor is directed to the self-heating RWGS reactor. The exhaust gas from the combustion-type RWGS reactor is typically between 700-900°C.

[0127] It is also conceivable that an autothermal RWGS reactor follows the electric RWGS reactor. In this case, the exhaust gas from the electric RWGS reactor is typically between 700-900°C.

[0128] The present invention also provides a heat exchange reactor (HER) for converting a first gas feed containing CO2 and H2 into a synthesis gas stream via a CO2 shift reaction of the first gas feed. The HER includes:

[0129] At least one process side and at least one heating side, wherein the process side of the HER includes a process side inlet and a process side outlet.

[0130] The process-side inlet is configured to supply the first gas feed containing CO2 and H2 to the process side.

[0131] The process-side outlet is arranged to output the synthesis gas stream from the process side, which optionally mixes with a cooling fluid.

[0132] The process side of HER includes a first reaction zone (I) located closest to the process side inlet.

[0133] Furthermore, the process side of HER includes a second reaction zone (II) located closest to the process side outlet.

[0134] The first reaction zone (I) is arranged to carry out the overall exothermic reaction of the first gas feed, wherein the overall exothermic reaction includes at least the following reactions, which have a net progression from left to right:

[0135]

[0136]

[0137] The second reaction zone (II) is arranged to perform a total endothermic reaction on the gas from the first reaction zone, wherein the total endothermic reaction includes at least the following reactions, which have a net progression from left to right:

[0138]

[0139]

[0140] The heating side of HER includes a heating side inlet and an optional heating side outlet.

[0141] The heating-side inlet is arranged to supply heating fluid to the heating side.

[0142] The heating-side outlet (if present) is arranged to output cooled fluid from the heating side.

[0143] The at least one process side and the at least one heating side are arranged such that heat transfer from the heating side to the process side is possible.

[0144] The system may also include any additional units and connections (e.g., pipes) that a person skilled in the art may deem necessary.

[0145] The process side of the HER suitably has a total length extending from the process side inlet to the process side outlet, and wherein the first reaction zone (I) has an extension of less than 50%, for example less than 30%, preferably less than 20%, more preferably less than 10% of the total length of the HER process side. A first catalyst is suitably located at least in the first reaction zone (I) of the HER. At least one end of the process side of the first reaction zone (I) is not in direct contact with the heating side of the HER, said end being located closest to the process side inlet of the HER and having an extension of up to 25% of the total process side extension of the first reaction zone in the direction from the process side inlet to the process side outlet, such that this end of the first reaction zone (I) is heated primarily by an adiabatic temperature rise caused by the exothermic reaction in the first reaction zone (I). In particular, said end has an extension of 5-20%, preferably 5-10%, of the total process side extension of the first reaction zone in the direction from the process side inlet to the process side outlet. The HER is suitably a bayonet-type HER. The HER may have at least two process sides and / or at least two heating sides.

[0146] The H2 / CO ratio of the syngas output from the HER is appropriately 1.8 to 2.2, for example, 1.9 to 2.1. This is desirable, for example, if the syngas is used to synthesize fuels such as kerosene or diesel via downstream synthesis through Fischer-Tropsch synthesis.

[0147] In one implementation, the (H2-CO2) / (CO+CO2) ratio (also known as the syngas modulus) of the syngas stream output from the HER is 1.8 to 2.2, for example, 2.0 to 2.1. This is desirable, for example, if the syngas is used for downstream synthesis of methanol.

[0148] The overall exothermic reaction of the first gas feed takes place in the first reaction zone (I); the overall endothermic reaction of the gas from the first reaction zone (I) takes place in the second reaction zone (II); and the synthesis gas stream is optionally mixed with a cooled fluid and discharged from the process side (of the HER) via a process-side outlet. The cooled fluid may be discharged from the heated side of the HER via a heated-side outlet.

[0149] The gas temperature in the first reaction zone (I) is typically 300-800℃. The gas temperature in the second reaction zone (II) is typically 600-1200℃.

[0150] Appropriately, process conditions are adjusted to provide a synthesis gas stream and / or a cooled fluid and / or a third product stream with temperatures at the corresponding outlet of the HER above the critical limit for metal dusting. This means that the temperature is high enough that there is no thermodynamic potential for metal dusting, or that the thermodynamic potential is low enough that metal dusting does not occur or occurs at a very low rate.

[0151] For example, the cooling outlet temperature of the synthesis gas stream and / or the cooled fluid and / or the third product stream is 500°C or higher, 600°C or higher, 700°C or higher, or 800°C or higher. By controlling the temperature of the cooled product stream, the risk of metal dusting can be controlled, where, due to the exothermic nature of the related reactions, generally lower temperatures favor (and undesirably) increasing the potential for metal dusting (higher a... c ).

[0152] The synthesis gas stream and / or the cooled fluid and / or the third product stream appropriately have a CO reduction reaction actual gas carbon activity of less than 100, or less than 50, or less than 10, or less than 5, or less than 1 at the cooling outlet temperature.

[0153] Typically, the H2 / CO ratio of the synthesis gas stream and / or cooling fluid and / or third product stream is in the range of 0.5 to 3.0, for example, in the range of 1.9 to 2.1 or in the range of 2 to 3. Furthermore, the (H2-CO2) / (CO+CO2) ratio of the synthesis gas stream and / or cooling fluid and / or third product stream can be in the range of 1.5 to 2.5, for example, in the range of 1.9 to 2.1 or in the range of 2 to 2.05.

[0154] The control of the cooling outlet temperature of the synthesis gas stream and / or the cooled fluid and / or the third product stream can be achieved through appropriate design of the HER reactor. One way to achieve this is to minimize or eliminate heat transfer from the heating side to the process side in the reaction zone (I). As described above, in a preferred embodiment, most or all of the temperature rise in the reaction zone (I) is caused by an adiabatic temperature rise resulting from the methanation reaction using a non-selective catalyst. In a preferred embodiment, the gas temperature leaving the first reaction zone (I) is above 650°C, more preferably above 700°C, and most preferably above 750°C. If no heat transfer occurs between the process side and the heating side in the reaction zone (I), the gas temperature leaving the HER reactor from the heating side must be higher than the gas temperature leaving the reaction zone (I) from the process side. Therefore, one means of maintaining a high temperature of the gas leaving the HER reactor from the heating side (e.g., the cooled first product gas) is to prevent or minimize heat transfer in the reaction zone (I) of the HER reactor. This can be achieved, for example, by:

[0155] 1) As mentioned above, an adiabatic nonselective catalyst is installed upstream of the HER reactor.

[0156] 2) Most or all of the first reaction zone (I) is not in direct thermal contact with the heating side of the HER.

[0157] 3) Provide, at least in the reaction zone (I) portion of the HER reactor between the process side and the heating side, a device such as insulation.

[0158] In one embodiment according to 1) or 2) above, the first gas feed undergoes an adiabatic reaction according to reactions (1) and (2) until (or close to) equilibrium.

[0159] The mixing unit can be located downstream of the HER and arranged to mix the synthesis gas stream and the cooling fluid. This arrangement is advantageous when both the synthesis gas stream and the cooling fluid are used for the same downstream application, and therefore mixing can also take place within the HER, thus maximizing the utilization of the heat transfer area in the equipment.

[0160] HERs may have two separate heating sides. Such HERs are like... Figure 3 As shown.

[0161] In a particular embodiment, the HER comprises multiple twin tubes. A twin tube is understood as two concentric tubes of similar length, wherein the diameter of the inner tube is smaller than the diameter of the outer tube. In this arrangement, a catalyst is placed in the inner tube and between the outer tubes. A portion of the first feed gas flows from the HER reactor inlet through the catalyst-filled inner tube to the other end of the HER reactor. The remainder of the first feed gas flows through the catalyst-filled region between the outer tubes. A heating fluid consists of the gas exiting the catalyst-filled inner tube and mixes with the syngas in the catalyst-filled region between the outer tubes, producing a third product gas. The third product gas flows in a substantially countercurrent manner through the annular space between the inner and outer tubes, producing a cooled third product gas. The cooling of the third product gas provides the necessary heat to the process side (the region between the catalyst-filled inner and outer tubes). This is an example of a system where the HER has two process sides.

[0162] In another embodiment, the third product stream is further cooled in a heat exchanger (waste heat boiler), where the heat is used to generate steam from the water stream. The temperature of this further cooled third product stream is typically 300-550°C. The generated steam can be used for various purposes, such as for power generation or as a feed stream for an electrolysis unit used to produce hydrogen. In this case, the electrolysis unit can be arranged in series with the HER reactor. The hydrogen produced in the electrolysis unit can be added directly to the HER reactor as part or all of the hydrogen in the first gas feed.

[0163] The further cooled third product stream may have a temperature of 300-550°C after being used for steam generation as described above. This further cooled third product stream can then be used for additional heating, such as preheating part or all of the first gas feed. Even if the further cooled third product stream has a high carbon monoxide content, severe metal dusting can be avoided due to the sufficiently low temperature of the heat transfer surfaces.

[0164] The third product stream can be used as a heat source, for example, to preheat part or all of the first gas feed. This has the advantage of optimizing energy efficiency. The preheating of the first gas stream and the generation of steam can be carried out in parallel or in series.

[0165] In one aspect, the system may further include a combustion unit and a fourth fuel feed, wherein the third fuel feed is arranged to be supplied to the combustion unit and combusted in the combustion unit in the presence of an oxidant to provide a fifth combustion gas feed, wherein the fifth feed is arranged to be supplied as part or all of the heating fluid to the heating side of the HER. Preferably, the oxidant in the combustion unit is substantially pure oxygen, preferably greater than 90% oxygen, and most preferably greater than 99% oxygen. This allows for an increased option of transfer load on the HER, thereby promoting increased CO production in the second product stream.

[0166] The third fuel feed can be a hydrogen-containing feed, which is combusted into a fifth feed, which is a steam-containing feed. When the fifth feed is mixed with the syngas stream, it is advantageous to have substantially pure steam as the fifth feed, because the steam can be easily removed again without affecting the product quality of the syngas produced.

[0167] Alternatively, the third fuel feed can be a feed comprising methane and / or other hydrocarbons, such that the fifth feed is a feed comprising carbon dioxide and steam. CO2 can thus be advantageously recovered from downstream of the HER and used as input to the upstream feedstock. In one embodiment, the external burner employs substoichiometry, and the fifth feed can comprise CH4, CO, and / or H2. In particular, it is advantageous if H2 is substoichiometric relative to O2.

[0168] As described above, when the fifth feed is fed separately to the heating side of the HER, the cooled fifth feed can be used downstream of the HER as part of the first gas feed containing CO2 and H2. Cooling of this feed may cause some of the vapor within it to condense.

[0169] Typically, the fifth feed is cooled sufficiently to condense H2O before being conveyed to the feed side (see...). Figure 7 Therefore, the system may include an optional condensation stage.

[0170] Syngas produced by the above system and method can be used, for example, to produce methanol, synthetic gasoline, synthetic jet fuel, or synthetic diesel. Detailed Implementation

[0171] Figure 1 A general embodiment of the HER 20 of the present invention is shown. A first gas feed 2 is supplied to the process side 20A of the HER 20 via a process-side inlet 28. A heating fluid 11 is supplied to the heating side 20B of the HER 20, such that heat from the heating fluid 11 is transferred to the process side 20A of the HER 20. This facilitates the conversion of the first gas feed 2 into a synthesis gas stream 21 containing CO in the process side 20A of the HER 20; wherein the overall exothermic reaction of the first gas feed 2 occurs in a first reaction zone (I); and the overall endothermic reaction of the gas from the first reaction zone (I) occurs in a second reaction zone (II). A cooled fluid 31 is output from a heating-side outlet 27. The outlet temperature of the cooled fluid 31 from the HER is approximately 500°C or higher.

[0172] Figure 2 Another embodiment of HER 20 is shown, which is a bayonet-type HER. Reference symbols are as follows. Figure 1 As shown.

[0173] Figure 3 A general implementation of system 100 is shown, comprising the HER 20 of the present invention and a reverse water gas shift (RWGS) reactor 10. A first feed 1 containing CO2 and H2 is supplied to the RWGS reactor 10, where it is also converted into a first product stream 11; i.e., a synthesis stream. The outlet temperature of the RWGS reactor (i.e., the first product stream 11) is greater than 1000°C, thus this stream can be used as a heating fluid in the downstream HER. A first feed 2 is supplied to the process side 20A of the HER 20, where it is converted into a synthesis stream 21. The HER operates at an outlet temperature of 950°C (i.e., the temperature of the synthesis stream 21). The first product stream 11 is supplied to the heating side 20B of the HER 20, such that heat from the first product stream 11 is transferred to the process side 20A of the HER 20. This facilitates the conversion of the second feed 2 into a second product stream 21 containing CO in the process side 20A of the HER 20; and provides a cooled first product stream 31. The outlet temperature of the first product stream 31 from the HER is approximately 500°C or higher.

[0174] Figure 4 It showed something similar to Figure 3 The implementation of system 100, wherein reference symbols are as follows: Figure 3As shown. Furthermore, for this system, the primary feed 9, containing CO2 and H2, is divided into a first feed 2 and a second feed 1. The feed rate of the primary feed 9 is 10000 Nm. 3 The feed rate is [h], and it contains approximately 70% H2 and 30% CO2. In this embodiment, the first and second feeds have equal molar amounts. Further details are as follows: Figure 3 As shown.

[0175] exist Figure 5 In the implementation method, a method similar to Figure 4 System 100, where reference symbols are as follows Figure 4 As shown. Furthermore, HER 20 has a first heating side 20B' and a second heating side 20B'". Heating fluid 11 is supplied to the first heating side 20B', while synthesis gas flow 21 is supplied to the second heating side 20B'. Cooling fluid 31 is output from the first heating side 20B' of the HER, while cooled synthesis gas flow 32 is output from the second heating side 20B'".

[0176] exist Figure 6 In the implementation method, a method similar to Figure 3 System 100, where reference symbols are as follows Figure 3 As shown. Furthermore, the system includes a combustion unit 30 and a third fuel feed 4. The third fuel feed 4 is arranged to be supplied to the combustion unit 30 and combusted in 30 in the presence of an oxidant 4B (typically an O2 stream) to provide a fifth combustion gas feed 5. The fifth feed 5 is supplied to the heating side 20B of the HER as an additional heat source.

[0177] Figure 7 It showed something similar to Figure 6 System 100, wherein the first feed 2 and the second feed 1 are coupled with... Figure 4 The same implementation method originates from the same primary feed 9.

[0178] Figure 7A The implementation method in is based on Figure 5 The implementation method is as follows. In this implementation, the fifth combustion gas feed 5 passes through the heating side of the HER, and the cooled fifth feed 25 is used downstream of the HER as part of the second feed 1 and / or as part of the first feed 2 containing CO2 and H2. In the illustrated implementation, the flash separator 40 is used to remove the water stream 41, and the remainder of the fifth feed 25 is recycled to the primary feed 9.

[0179] Figure 7B The implementation method in is based on Figure 7A In this embodiment, the heating fluid 11 is combined with the synthesis gas flow 21 to form a third product flow, which is supplied to the heating side of the HER.

[0180] Figure 11 An alternative arrangement of the HER of the present invention is shown, wherein the synthesis gas flow 21 and the cooling fluid 31 are combined before the HER outlet.

[0181] Example

[0182] Comparative Example 1

[0183] As a first comparative example, a standalone e-RWGS reactor with a non-selective catalyst is used in this case for illustration. Table 1 summarizes the operation of this process, in which a 10000 Nm³ reactor containing 69.2% H₂ and 30.8% CO₂ is used in the e-RWGS reactor. 3 The total feed per hour is converted into syngas with an H2 / CO ratio of 1.88, equivalent to producing 1340 kcal / Nm³. 3 CO.

[0184] Table 1

[0185] T[℃] 450 1050 P[barg] 11.5 10.0 <![CDATA[flow rate [Nm 3 / h]]]> 10000 9988 Composition [moles %] <![CDATA[H2]]> 69.2 45.1 <![CDATA[CO2]]> 30.8 6.8 <![CDATA[N2]]> 0.0 0.0 CO 0.0 24.0 <![CDATA[H2O]]> 0.0 24.1 <![CDATA[CH4]]> 0.0 0.1

[0186] Example 2

[0187] As a first embodiment of the invention, Table 2 shows a combination of e-RWGS and HER for producing syngas suitable for Fischer-Tropsch synthesis. In this case, a 10000 Nm³ gas containing 69.2% H₂ and 30.8% CO₂ is used. 3 The primary feed at / h is separated into equimolar amounts of first and second feeds, which are supplied to the e-RWGS and HER, respectively. The stream from the e-RWGS is heated to 1050°C and thermodynamically converted to produce syngas with an H2 / CO ratio of 1.88. The HER operates at an outlet temperature of 950°C (partly given by the available temperature of the heated gas) and receives 50% of the molar flow rate from the primary feed (i.e., 50% of the combined molar flow rate of the first and second feeds). The first and second product streams are mixed and used as a heat source for the HER, which cools the gas to 646°C, leaving a driving force of 196°C for heat exchange. Overall, the combined syngas has an H2 / CO ratio of 1.94, which is slightly higher than the comparative example. However, this also only uses 689 kcal / Nm³. 3 CO is produced, which reduces the load by 49% compared to the comparative example. Specifically, the e-RWGS requires a load of 1.6 Gcal / h, while the load transferred to the process side of the HER is 1.4 Gcal / h; therefore, the HER accounts for 46% of the total transfer load on the process side between the two reactors. This load distribution roughly reflects the division of CO production, with 49% of CO production completed in the HER.

[0188] The carbon activity of the CO reduction reaction of the combined (i.e., third) cooling product gas is 6.2.

[0189] Table 2.

[0190] T[℃] 450 450 1050 950 646 P[barg] 11.5 11.5 10.0 10.0 9.5 <![CDATA[Flow rate [Nm 3 / h]]]> 5000 5000 4994 4968 9962 Composition [moles %] <![CDATA[H2]]> 69.2 69.2 45.1 45.6 45.3 <![CDATA[CO2]]> 30.8 30.8 6.8 7.9 7.3 <![CDATA[N2]]> 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 24.0 22.8 23.4 <![CDATA[H2O]]> 0.0 0.0 24.1 23.4 23.8 <![CDATA[CH4]]> 0.0 0.0 0.1 0.3 0.2

[0191] Example 3

[0192] In another embodiment, Table 3 illustrates the combination of e-RWGS and HER, demonstrating how HER can become the primary CO production unit. In this case, a 10,000 Nm³ of CO containing 69.2% H₂ and 30.8% H₂ will be used. 3 The primary feed is separated into a first feed and a second feed, accounting for 45% and 55% of the total molar flow rate, respectively. The stream from the e-RWGS is heated to 1050°C and thermodynamically converted to produce syngas with an H2 / CO ratio of 1.88. The HER operates at an outlet temperature of 905°C (partly given by the available temperature of the heated gas) and receives 55% of the molar flow rate from the primary feed (i.e., 55% of the combined molar flow rate of the first and second feeds). The first and second product streams are mixed and used as a heat source for the HER, which cools the gas to 621°C, leaving a driving force of 171°C for heat exchange. Overall, the combined syngas has an H2 / CO ratio of 1.98, which is slightly higher than the comparative example. However, this also only uses 637 kcal / Nm³. 3 CO is produced, which reduces the load by 52% compared to the comparative example. Specifically, the e-RWGS requires a load of 1.4 Gcal / h, while the load transferred to the process side of the HER is 1.3 Gcal / h; therefore, the HER accounts for 48% of the total transfer load on the process side between the two reactors. This load distribution roughly reflects the division of CO production, with 52% of CO production completed in the HER.

[0193] The carbon activity of the CO reduction reaction of the combined (i.e., third) cooling product gas is 73.

[0194] Table 3.

[0195] T[℃] 450 450 1050 905 621 P[barg] 11.5 11.5 10.0 10.0 9.5 <![CDATA[flow rate [Nm 3 / h]]]> 4500 5500 4495 5420 9915 Composition [moles %] <![CDATA[H2]]> 69.2 69.2 45.1 45.4 45.2 <![CDATA[CO2]]> 30.8 30.8 6.8 8.6 7.8 <![CDATA[N2]]> 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 24.0 21.9 22.8 <![CDATA[H2O]]> 0.0 0.0 24.1 23.4 23.7 <![CDATA[CH4]]> 0.0 0.0 0.1 0.7 0.4

[0196] Example 4

[0197] In another embodiment, Table 4 shows a combination of e-RWGS and HER, illustrating how HER operation can be configured to have a very low metal dusting drive force. In this case, a 10000 Nm³ of metal containing 69.2% H₂ and 30.8% H₂ will be used. 3The primary feed at / h is separated into a first feed and a second feed, accounting for 60% and 40% of the total molar flow rate, respectively. The stream from the e-RWGS is heated to 1050°C and thermodynamically converted to produce syngas with an H2 / CO ratio of 1.88. The HER operates at an outlet temperature of 915°C (partly given by the available temperature of the heated gas) and receives 40% of the molar flow rate from the primary feed (i.e., 40% of the combined molar flow rate of the first and second feeds). The first and second product streams are mixed and used as the heating source for the HER, which cools the gas to 737°C. Overall, the combined syngas has an H2 / CO ratio of 1.95, which is slightly higher than the comparative example. However, this also only uses 832 kcal / Nm³. 3 CO is produced, which reduces the load by 38% compared to the comparative example. Specifically, the e-RWGS requires a load of 1.9 Gcal / h, while the load transferred to the process side of the HER is 1.0 Gcal / h; therefore, the HER accounts for 34% of the total transfer load on the process side between the two reactors. This load distribution roughly reflects the division of CO production, with 38% of CO production completed in the HER.

[0198] In the current configuration of the HER, the first reaction zone (I) of the HER is exothermic, which generates a high temperature rise on the process side, thus resulting in a lower temperature for cooling the heating gas. This control means that the carbon activity cannot be further increased. Figure 8 As shown, the temperature of the gas on the HER heating side and the actual gas carbon activity curves clearly illustrate these details. It can be seen here that the carbon activity used for the CO reduction reaction does not exceed 1.6.

[0199] Table 4.

[0200] T[℃] 450 450 1050 915 738 P[barg] 11.5 11.5 10.0 10.0 9.5 <![CDATA[Flow rate [Nm 3 / h]]]> 6000 4000 5993 3952 9945 Composition [moles %] <![CDATA[H2]]> 69.2 69.2 45.1 45.5 45.2 <![CDATA[CO2]]> 30.8 30.8 6.8 8.4 7.4 <![CDATA[N2]]> 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 24.0 22.1 23.2 <![CDATA[H2O]]> 0.0 0.0 24.1 23.4 23.8 <![CDATA[CH4]]> 0.0 0.0 0.1 0.6 0.3

[0201] Example 5

[0202] In another embodiment, Table 5 shows a combination of e-RWGS and HER, illustrating how this configuration can be used to produce syngas suitable for methanol production with high CO content. In this case, a 10,000 Nm³ / h syngas containing 75% H₂ and 25% CO₂ will be used. 3The primary feed at / h is separated into a first feed and a second feed, accounting for 60% and 40% of the total molar flow rate, respectively. The stream from the e-RWGS is heated to 1050°C and thermodynamically converted to produce syngas with an H2 / CO ratio of 2.6. The HER operates at an outlet temperature of 930°C (partially given by the available temperature of the heated gas) and receives 40% of the molar flow rate from the primary feed (i.e., 40% of the combined molar flow rate of the first and second feeds). The first and second product streams are mixed and used as the heating source for the HER, which cools the gas to 750°C. Overall, the combined syngas has an H2 / CO ratio of 2.68 and a modulus of 2.0 suitable for methanol production. This is also achieved using 899 kcal / Nm³. 3 CO is produced. Specifically, the e-RWGS requires a load of 1.8 Gcal / h, while the load transferred to the process side of the HER is 0.9 Gcal / h; therefore, the HER accounts for 34% of the total transfer load on the process side between the two reactors. This load distribution roughly reflects the division of CO production, with 38% of CO production completed in the HER.

[0203] In the current configuration of the HER, the first reaction zone (I) is exothermic, which generates a high temperature rise on the process side, thus resulting in a lower temperature for cooling the heating gas. This control means that carbon activity cannot be further increased. Figure 9 In the given embodiment shown, the temperature of the gas on the HER heating side and the actual carbon activity of the gas clearly illustrate these details. It can be seen here that the carbon activity used for the CO reduction reaction does not exceed 1.5.

[0204] Table 5.

[0205] T[℃] 450 450 1050 930 750 P[barg] 11.5 11.5 10.0 10.0 9.5 <![CDATA[Flow rate [Nm 3 / h]]]> 6000 4000 5988 3941 9929 Composition [moles %] <![CDATA[H2]]> 75.0 75.0 54.0 53.8 53.9 <![CDATA[CO2]]> 25.0 25.0 4.2 5.3 4.7 <![CDATA[N2]]> 0.0 0.0 0.0 0.0 0.0 CO 0.0 0.0 20.7 19.3 20.2 <![CDATA[H2O]]> 0.0 0.0 20.9 20.8 20.9 <![CDATA[CH4]]> 0.0 0.0 0.1 0.7 0.4

[0206] Example 6

[0207] In another embodiment, Table 5 shows a combination of e-RWGS and HER, illustrating how this configuration can be used to similarly process primary feedstocks containing methane. In this case, a 10000 Nm³ feedstock containing 56.8% H₂, 22.7% CO₂, 11.4% CH₄, and 9.1% H₂O will be used. 3The primary feed is separated into a first feed and a second feed, accounting for 70% and 30% of the total molar flow rate, respectively. The stream from the e-RWGS is heated to 1050°C and thermodynamically converted to produce syngas with an H2 / CO ratio of 2.37. The HER operates at an outlet temperature of 912°C (partially given by the available temperature of the heated gas) and receives 30% of the molar flow rate from the primary feed (i.e., 30% of the combined molar flow rate of the first and second feeds). The first and second product streams are mixed and used as the heating source for the HER, which cools the gas to 682°C. Overall, the combined syngas has an H2 / CO ratio of 2.41. This is achieved using 1456 kcal / Nm³. 3 The CO production is completed in the HER, with a portion of the load used for the more endothermic reforming reaction. Specifically, the e-RWGS requires a load of 4.2 Gcal / h, while the load transferred to the process side of the HER is 1.4 Gcal / h; therefore, the HER accounts for 26% of the total transfer load on the process side between the two reactors. This load allocation roughly reflects the division of CO production, with 27% of CO production completed in the HER.

[0208] In the current configuration of the HER, the first reaction zone (I) is exothermic, which generates a high temperature rise on the process side, thus resulting in a lower temperature for cooling the heating gas. This control means that carbon activity cannot be further increased. Figure 10 In the given embodiment shown, the temperature of the gas on the HER heating side and the actual gas carbon activity curves clearly illustrate these details. It can be seen here that the carbon activity used for the CO reduction reaction does not exceed 0.3.

[0209] Table 5.

[0210]

[0211]

[0212] The invention has been described with reference to various aspects and embodiments. These aspects and embodiments can be combined in any way by those skilled in the art while remaining within the scope of the claims of this patent.

Claims

1. A method for converting a first gas feed (2) into a synthesis gas stream via a CO2 shift reaction in a heat exchange reactor HER (20) comprising CO2, H2, and 0-5 vol% CO, wherein the HER (20) comprises: At least one process side (20A) and at least one heating side (20B), wherein the process side (20A) of the HER (20) includes a process side inlet (28) and a process side outlet (29). The process side (20A) of the HER (20) includes a first reaction zone (I) located closest to the process side inlet (28). Furthermore, the process side (20A) of the HER (20) includes a second reaction zone (II) located closest to the process side outlet (29). The heating side (20B) of the HER includes a heating side inlet (26) and an optional heating side outlet (27). The at least one process side (20A) and the at least one heating side (20B) are arranged such that heat transfer from the heating side (20B) to at least a portion of the process side (20A) is possible. The method includes the following steps: - The first gas feed (2) is supplied to the process side (20A) of the HER (20) via the process side inlet (28); - Heating fluid (11) is supplied to the heating side (20B) of the HER via the heating side inlet (26), and heat transfer from the heating fluid (11) to the process side (20A) of the HER (20) is allowed; - The overall exothermic reaction of the first gas feed (2) is carried out in the first reaction zone (I), wherein the overall exothermic reaction includes at least the following reactions, which have a net progression from left to right: CO (g) + 3 H2 (g) CH4 (g) + H2O (g) (2) CO2(g) + H2 (g) CO (g) + H2O (g) (1); - A total endothermic reaction of the gas from the first reaction zone (I) is carried out in the second reaction zone (II), wherein the total endothermic reaction comprises at least the following reactions, which have a net progression from left to right: CH4 (g) + H2O CO (g) + 3H2 (g) (reverse reaction of (2)) CO2(g) + H2 (g) CO (g) + H2O (g) (1) - Optionally, the cooled fluid (31) is discharged from the heating side (20B) via the heating side outlet (27); - The synthesis gas stream (21) is discharged from the process side (20A) via the process side outlet (29), which optionally mixes with the cooled fluid (31); The end of the first reaction zone (I) near the process side inlet of the HER is not in direct contact with the heating side of the HER. The end has a total extension of 5-20% of the process side of the first reaction zone in the direction from the process side inlet to the process side outlet, such that the end of the first reaction zone (I) is mainly heated by the adiabatic temperature rise caused by the exothermic reaction. The heating fluid (11) and at least a portion of the synthesis gas flow (21) leaving the second reaction zone are combined inside the HER (20) and recycled as at least a portion of the heating fluid (11); The catalyst is a non-selective catalyst, which is active for both reactions (1) and (2); and The temperature of the first gas feed is 250 to 550°C.

2. The method according to claim 1, wherein the gas temperature in the first reaction zone (I) is 300-800°C.

3. The method according to claim 1, wherein the gas temperature in the second reaction zone (II) is 600-1200°C.

4. The method of claim 1, wherein the synthesis gas stream (21) and the cooling fluid (31) are combined to provide a third product stream (35).

5. The method according to claim 4, wherein the process conditions are adjusted such that the temperature of the synthesis gas stream (21) and / or the cooled fluid (31) and / or the third product stream (35) at the respective outlet of the HER (20) is above the critical limit for metal pulverization.

6. The method according to claim 4, wherein the cooling outlet temperature of the synthesis gas stream (21) and / or the cooling fluid (31) and / or the third product stream (35) is 500°C or higher.

7. The method according to claim 6, wherein the synthesis gas stream (21) and / or the cooled fluid (31) and / or the third product stream (35) have a CO reduction reaction actual gas carbon activity of less than 100 at the cooled outlet temperature.

8. The method according to claim 4, wherein the H2 / CO ratio of the synthesis gas stream (21) and / or the cooling fluid (31) and / or the third product stream (35) is in the range of 0.5 to 3.

0.

9. The method according to claim 4, wherein the (H2-CO2) / (CO+CO2) ratio of the synthesis gas stream (21) and / or the cooling fluid (31) and / or the third product stream (35) is in the range of 1.5 to 2.

5.

10. The method according to any one of claims 1-9, wherein the ratio of H2 to CO2 in the first gas feed is 1-5.

11. The method according to any one of claims 1-9, wherein the molar ratio of CH4 / CO2 in the first gas feed is less than 0.

5.

12. The method according to any one of claims 1-9, wherein the first gas feed (2) further comprises up to 3 mol% methane.

13. The method according to any one of claims 1-9, wherein the heating fluid (11) is provided by an electric RWGS (e-RWGS) reactor (10A), a combustion RWGS reactor (10B), or a self-heating RWGS reactor (10C).

14. The method according to any one of claims 1-9, wherein the heating fluid (11) comprises CO2 and H2.

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