ATR reforming

Abstract

The invention relates to a syngas stage in which an electrical heating unit is located between a pre-reformer stage and an ATR stage. A first electrical heating unit is arranged to heat the pre-reformed stream to at least 400 DEG C, and then feed it to the ATR section. The invention also relates to a method for producing a first syngas stream, a hydrogen production plant (which can be used in hydrogen, ammonia, methanol and synthetic fuel production plants) and a method for reducing CO2 emissions from a hydrogen production plant.

Description

Technical Field

[0001] The invention relates to a synthesis gas stage, wherein an electric heating unit is located between a pre-reformer section and a reforming section. A first electric heating unit is arranged to heat the pre-reformed stream to at least 400°C before feeding it to the reforming section. In this way, one or more fired heaters can be avoided. The invention also relates to a method for producing a first synthesis gas stream and a production plant (such as a hydrogen production plant, an ammonia plant, a methanol plant and a synthetic fuel production plant comprising the synthesis gas stage) and a method for reducing CO2 emissions from the plant. Background Art

[0002] There are significant efforts to optimize the production of hydrogen production facilities, aiming to improve overall energy efficiency and reduce capital costs. The need for more cost-effective hydrogen production has driven the development of technologies and catalysts for large-scale hydrogen production units to benefit from economies of scale. There are also efforts to reduce greenhouse gas emissions from such facilities.

[0003] Reducing CO2 emissions from hydrogen production facilities (among other things) would have significant advantages.

[0004] WO2022038089 describes an apparatus for producing a hydrogen-rich stream from a hydrocarbon feed. Summary of the invention

[0005] One object of the present invention is to reduce the consumption of hydrocarbon feed and fuel in a hydrogen production plant and / or method, thereby improving energy efficiency. At the same time, another object is to reduce CO2 emissions in a hydrogen production plant and / or method. The carbon footprint of the plant can be significantly reduced thereby.

[0006] The present invention achieves these and other objects.

[0007] Thus, in a first aspect, there is provided a synthesis gas stage comprising:

[0008] - a first hydrocarbon feed,

[0009] - a pre-reformer section arranged to receive said first hydrocarbon feed and to provide a pre-reformed stream,

[0010] a reforming section arranged to receive the pre-reformed stream and to provide a first synthesis gas stream,

[0011] Wherein the synthesis gas stage comprises a first electric heating unit located between the pre-reformer section and the reforming section, the first electric heating unit being arranged to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, before feeding it to the reforming section.

[0012] There is also provided a method of producing a first synthesis gas stream in the synthesis gas stage, the method comprising the steps of:

[0013] a. feeding the first hydrocarbon feed to the pre-reformer section and pre-reforming the first hydrocarbon feed to provide a pre-reformed stream;

[0014] b. feeding the pre-reformed stream to the first electric heating unit and heating the pre-reformed stream;

[0015] c. Feeding the heated pre-reformed stream to the reforming section and reforming it to provide a first synthesis gas stream.

[0016] Also provided are hydrogen plants, ammonia plants, methanol plants and synthetic fuel production plants comprising a synthesis gas stage as described herein.

[0017] The introduction of electric heaters enables a smooth start-up of the equipment. The use of electric heaters powered by renewable energy improves the overall carbon efficiency of the equipment.

[0018] Further details of the invention are given in the following description, drawings, aspects and dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This technique is illustrated by the following schematic diagram, where:

[0020] Figure 1 A simplified layout of one aspect of the system of the present invention is shown.

[0021] Figure 2 A further developed layout of the system according to the invention is shown.

[0022] Figure 3 A further developed layout of the system according to the invention is shown.

[0023] Figure 4 A developed layout of the system of the invention including a hydrogen production plant of the developed layout is shown. DETAILED DESCRIPTION OF THE INVENTION

[0025] Unless otherwise indicated, any given percentages of gas content are in volume %. All feeds were preheated as required.

[0026] For the avoidance of doubt, the term "feed" refers to means, such as pipes, tubes, etc., for supplying the gas to the appropriate stage, reactor or unit.

[0027] A "stage" includes one or more "units" that effect a change in the chemical composition of a feed, and may also include elements that do not change the chemical composition of a feed or stream, such as heat exchangers, mixers, or compressors.

[0028] Similarly, a "stage" consists of one or more segments.

[0029] The term "synthesis gas" (abbreviated as "syngas") refers to a gas containing hydrogen, carbon monoxide, carbon dioxide, water vapor and small amounts of other gases (such as argon, nitrogen, methane, etc.).

[0030] In a first aspect, a synthesis gas stage is provided. The output of the stage is a synthesis gas ("syngas") stream, for example comprising CO, H2, H2O, CO2, CH4 and mixtures thereof.

[0031] Syngas stage

[0032] In a first aspect, there is provided a synthesis gas stage, the stage comprising:

[0033] - a first hydrocarbon feed,

[0034] - a pre-reformer section arranged to receive said first hydrocarbon feed and to provide a pre-reformed stream,

[0035] a reforming section arranged to receive the pre-reformed stream and to provide a first synthesis gas stream,

[0036] Wherein the synthesis gas stage comprises a first electric heating unit located between the pre-reformer section and the reforming section, the first electric heating unit being arranged to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, before feeding it to the reforming section.

[0037] A first hydrocarbon feed is provided. The first hydrocarbon feed suitably comprises a majority of methane, such as more than 80%, preferably more than 90% methane. Higher hydrocarbons (containing> 2 carbon atoms) may also be present. Suitably, the first hydrocarbon feed is a natural gas feed. The hydrocarbon feed may also contain small amounts of argon, nitrogen, carbon dioxide, steam and sulfides.

[0038] The pre-reformer section is arranged to receive the first hydrocarbon feed and provide a pre-reformed stream. Pre-reforming is a process of steam reforming methane and heavier hydrocarbons and methanating the reformed products of the heavier hydrocarbons. The pre-reformer section may include an adiabatic pre-reformer filled with a catalyst having a high nickel content and a main steam reformer. The adiabatic pre-reformer is typically located upstream of the main steam reformer. Steam may be added to the stream containing hydrocarbons upstream of the pre-reformer section. The pre-reformed stream provided contains CO2, CH4, H2O and H2, as well as generally lesser amounts of CO and other possible components.

[0039] In the pre-reformer, all higher hydrocarbons can be converted into carbon oxides and methane, but the pre-reformer also has advantages for light hydrocarbons. The installation of a pre-reformer can bring several benefits, including reducing the required O2 consumption in the ATR and allowing the inlet temperature of the ATR to be increased, as the risk of cracking caused by preheating is minimized. In addition, the pre-reformer can provide effective sulfur protection, making the feed gas entering the ATR and downstream systems almost sulfur-free.

[0040] The reforming section is configured to receive a pre-reformed stream (from a pre-reformer section) and provide a first synthesis gas stream. Providing a pre-reformed stream to the reforming section has several advantages, including that the pre-reformer section can provide effective sulfur protection, so that the feed gas entering the reforming section and downstream systems is almost sulfur-free.

[0041] The reforming section comprises at least one of an autothermal reforming (ATR) section, a reverse water gas shift (RWGS) section (optionally, the reverse water gas shift section is electrically heated), a steam methane reformer (SMR) section, a steam methane reformer-b (SMR-b) section and / or a convective reformer (HTCR) section. In a preferred aspect, the reforming section comprises an autothermal reforming (ATR) section, and the ATR section is configured to receive a feed comprising an oxidant.

[0042] The ATR section may include one or more ATR reactors, such that the core of the ATR section is one or more ATR reactors. An ATR reactor typically includes a burner, a combustion chamber, and a catalyst bed contained within a refractory lined pressure shell. In the ATR reactor, hydrocarbons are partially combusted by a substoichiometric amount of an oxidant such as oxygen, and the partially combusted hydrocarbons are subsequently steam reformed in a fixed bed of a steam reforming catalyst (Reactions 1 and 2).

[0043]

[0044] Due to the high temperatures, a certain degree of steam reforming also occurs in the combustion chamber. The steam reforming reaction is accompanied by the water-gas shift reaction. Typically, at the reactor outlet, the gas is at or close to equilibrium with respect to steam reforming and water-gas shift reactions. More details and a complete description of ATR can be found in the art, for example, "Studies in Surface Science and Catalysis, Vol. 152, "Synthesis gas production for FT synthesis"; Chapter 4, p. 258-352, 2004").

[0045] Since the ATR section requires a substoichiometric amount of an oxidant (such as oxygen) to achieve partial combustion of hydrocarbons, a feed containing an oxidant is provided to the ATR section. Suitably, the oxidant feed consists essentially of oxygen. The oxidant feed of O2 is preferably "oxygen-enriched", meaning that the main component of the feed is O2; that is, more than 75%, such as more than 90% or more than 95%, or even more than 99% of the feed is O2. The oxidant feed may also contain other components, such as nitrogen, argon, CO2 and / or steam. The oxidant feed will typically contain a small amount of steam (e.g., 5-10%). The source of the oxidant (oxygen) feed may be at least one air separation unit (ASU) and / or at least one membrane unit. In addition, the source of oxygen may also be at least one electrolyzer unit. Part or all of the oxidant feed of O2 may come from at least one electrolyzer that uses electrical energy to convert steam or water into hydrogen and oxygen. Steam may be added to the oxidant feed containing oxygen upstream of the ATR section.

[0046] In a preferred aspect, the synthesis gas stage thus comprises a reforming section comprising an autothermal reforming (ATR) section, and said ATR section is arranged to receive a feed comprising an oxidant.

[0047] In another preferred aspect, the synthesis gas stage comprises a reforming section, the reforming section comprising an autothermal reforming (ATR) section, and further comprising an air separation unit and an air feed, the air separation unit being arranged to separate the air feed into at least an oxygen-rich stream and to supply at least a portion of the oxygen-rich stream to the ATR section as a feed comprising an oxidant. In this aspect, it is noted that, since the reforming section receives a pre-reformed stream, the stream mainly comprising CO2, CH4, H2O and H2, the required O2 consumption in the ATR reactor is reduced compared to an alternative in which the reforming section receives a hydrocarbon feed that has not been pre-reformed.

[0048] Typically, the exhaust gas stream from the ATR reactor, i.e. the first synthesis gas stream, has a temperature of 900-1100° C. Synthesis gas typically comprises hydrogen, carbon monoxide, carbon dioxide and steam. Other components such as methane, nitrogen and argon may also be present, but typically in smaller amounts. The operating pressure of the ATR reactor is 5 to 100 bar, more preferably 15 to 60 bar.

[0049] The synthesis gas stage further comprises a first electric heating unit located between the pre-reformer section and the reforming section. The first electric heating unit is arranged to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, before feeding it to the reforming section. The presence of the pre-reformer section upstream of the reforming section enables a reforming section comprising at least one reactor, such as at least one ATR reactor, to have a higher inlet temperature, since the risk of cracking caused by preheating is minimized. Essentially, the synthesis gas stage is arranged in such a way that there is no temperature variation between the electric heating unit and the reforming section.

[0050] In a conventional syngas stage, at least one fired heater is usually provided to preheat the pre-reforming stream upstream of the inlet of the reforming section. In order to reduce the carbon emissions of the fired heater, the inlet temperature of the reforming section is kept at a low level, for example below 450°C, such as 400°C. In order to completely avoid carbon emissions, the fired heater can also be eliminated. However, removing the fired heater complicates the operation and increases the difficulty of startup. Therefore, the syngas stage is configured to have an electric heater to heat the pre-reformed gas at the inlet of the reforming section (such as the inlet of the ATR section). Combining the electric heater with renewable electricity will not affect the carbon emissions of the syngas stage or the equipment containing the syngas stage. In this way, the electric heater using renewable electricity allows green energy to be provided to increase production for a given amount of O2, such as H2 production (for example, when the syngas stage is included in a hydrogen production device) without increasing CO2 emissions. In a preferred aspect, the reforming section comprises an autothermal reforming (ATR) section and the ATR section is configured to receive a feed comprising an oxidant (such as oxygen), whereby heating the pre-reforming stream to at least 450°C (such as 550°C or higher) will reduce oxygen consumption at the same synthesis gas production capacity, or increase synthesis gas production capacity at a given oxygen flow rate without any carbon emissions.

[0051] In conventional equipment, a fired heater is usually provided to preheat the pre-reforming flow entering the ATR. In order to reduce the carbon emissions of the fired heater, the inlet temperature of the ATR is kept at a low level, for example below 450°C, such as 400°C. In order to completely avoid carbon emissions, the fired heater can also be completely eliminated. However, removing the fired heater will make the operation of the equipment slightly complicated and also increase the difficulty of startup. Therefore, the equipment in the present invention is configured to have an electric heater to heat the pre-reforming gas entering the ATR. Combining the electric heater with renewable electricity will not affect the carbon emissions of the equipment. Heating the pre-reforming gas to at least 450°C (such as 550°C or higher) will reduce the oxygen consumption at the same synthesis gas generation capacity, or increase the synthesis gas generation capacity at a given oxygen flow rate without any carbon emissions.

[0052] Therefore, in a preferred aspect, the synthesis gas stage comprises a first electric heating unit, wherein the first electric heating unit is arranged to heat the pre-reformed stream to a temperature below 650°C.

[0053] In other aspects, the reforming section within the syngas stage may include a reverse water gas shift (RWGS) section, optionally wherein the reverse water gas shift unit is electrically heated. Electrically heated reverse water gas shift (e-RWGS) employs electrical resistance heating of the reactor to achieve a more efficient reverse water gas shift process and substantially reduce or preferably avoid the use of fossil fuels as a heat source. The e-RWGS section comprises at least one e-RWGS reactor. In the e-RWGS reactor, selective or non-selective RWGS may be performed, wherein "selective RWGS" means that only the reverse water gas shift reaction according to reaction 3 occurs,

[0054]

[0055] The reaction may be carried out on a catalyst or in a reactor, and "non-selective RWGS" means that in addition to the reverse water gas shift, other reactions occur, such as one or more methanation reactions (the reverse of reactions 1 and 2) and reverse methanation reactions.

[0056] In a preferred aspect and as an example, the reforming section comprises a non-selective RWGS. The RWGS reaction (3) is an endothermic process which requires a large amount of energy input to achieve the desired conversion, however the simultaneous methanation reaction in the reactor results in the release of chemical energy and heating of the system, resulting in an increase in temperature, since the methanation reaction is an exothermic reaction. Since the CO reduction reaction is also exothermic, the temperature increase caused by the methanation reaction results in a decrease in the potential energy of the CO reduction reaction, and when the temperature rises to a certain level, there is no potential energy for the CO reduction reaction at all. This specific level will depend on the specific reactant concentrations, inlet temperature and pressure, but will typically be in the range of 600-800°C, above which there is no possibility of CO reduction reaction occurring. Therefore, the e-RWGS reactor allows the temperature to be increased within the reactor from a relatively low inlet temperature (e.g., 400-600°C) to a higher product gas temperature across the entire reactor.

[0057] Therefore, in a preferred aspect, the reforming section within the synthesis gas stage comprises an e-RWGS section and a first electric heating unit located between the pre-reformer section and the reforming section, and the first electric heating unit is arranged to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, before feeding it to the reforming section.

[0058] In another aspect, the reforming section comprises a steam methane reforming (SMR) section or alternatively comprises an SMR-b section, wherein the SMR-b section comprises an SMR section arranged in parallel with the e-RWGS section. In a preferred aspect, the SMR section is electrically heated, so that it is an e-SMR section. The e-SMR section comprises at least one SMR reactor, wherein methane is typically steam heated in the presence of a catalyst to provide a mixture of carbon monoxide and hydrogen according to reaction 1. The e-SMR reactor benefits from receiving a preheated feed, such as a preheated pre-reformed hydrocarbon feed. In this way, a first electric heating unit is located between the pre-reformer section and the reforming section, and the first electric heating unit is configured in a preferred aspect to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, and then feed it to the reforming section.

[0059] In another aspect, the reforming stage comprises a convective reforming stage, such as a Haldor Convection reforming (HTCR) section. In this aspect, the SMR and ATR reforming processes are integrated so that the process of converting hydrocarbons and steam into hydrogen and carbon oxides is completely autothermal, thereby avoiding any external fuel combustion heating. Therefore, the HTCR section includes an integrated reactor, which is designed to include a primary reformer zone and a secondary reformer zone. The primary reformer zone receives a pre-reformed stream and provides an SMR reforming effluent, which enters the space at the feed end of the secondary reformer zone through a catalyst bed, where a preheated feed containing an oxidant (such as oxygen) is introduced so that the secondary reformer zone provides a secondary reformer effluent. The hot secondary reformer effluent does not leave the reactor, but passes through the shell side of the primary reforming zone, thereby providing the required heat for the endothermic SMR reforming reaction occurring in the catalyst-containing reactor tube of the primary reformer zone. Similar to ATR, e-RWGS and SMR reactors, such convective reforming comprising an integrated reactor benefits from receiving a preheated feed, such as a preheated pre-reformed hydrocarbon feed, thereby providing a first electric heating unit located between the pre-reformer section and the reforming section, which in a preferred aspect is arranged to heat the pre-reformed stream to at least 400°C, preferably at least 450°C, before feeding it to the reforming section.

[0060] In a preferred aspect, the synthesis gas stage is constructed such that it does not comprise a fired heater, in particular wherein the stage does not comprise a fired heater arranged to heat the pre-reformed stream before feeding it to the reforming section.

[0061] Desulfurization section

[0062] In one embodiment, the synthesis gas stage further comprises a desulfurization section, which is arranged to receive the first hydrocarbon feed and provide the desulfurized first hydrocarbon feed. Sulfur may be present in the hydrocarbon feed in the form of sulfides, however, it is not desirable for the stream entering the reforming section to contain sulfur, as the presence of sulfur generally leads to catalyst contamination, such as the formation of carbon deposits on the catalyst surface. Therefore, in a preferred aspect, the synthesis gas stage further comprises a desulfurization section arranged upstream of the reforming section, more preferably arranged upstream of the pre-reformer section.

[0063] In the aspect that the synthesis gas stage comprises a desulfurization section, the synthesis gas stage may further comprise a second electric heating unit located between the desulfurization section and the pre-reformer section. The second electric heating unit is configured to heat the desulfurized first hydrocarbon feed to at least 400°C, preferably at least 450°C, before feeding it to the pre-reformer section.

[0064] Therefore, in a preferred aspect, the synthesis gas stage also includes a desulfurization section, which is configured to receive a first hydrocarbon feed and provide a desulfurized first hydrocarbon feed; the synthesis gas stage also includes a second electric heating unit, which is configured to heat the desulfurized first hydrocarbon feed and then feed the desulfurized first hydrocarbon feed to the pre-reformer section.

[0065] Hydrogenation Section

[0066] In one aspect, the syngas stage comprises a desulfurization section, which may further comprise a hydrogenation section arranged to receive a first hydrocarbon feed and a hydrogen feed (optionally in mixed form) and to provide the hydrogenated first hydrocarbon feed to the desulfurization section.

[0067] In this aspect, the hydrogen feed is suitably "hydrogen-rich", meaning that the major part of the feed is hydrogen; i.e. more than 75%, such as more than 85%, preferably more than 90%, more preferably more than 95%, even more preferably more than 99% of the feed is hydrogen. Part or all of the hydrogen feed may come from at least one electrolyser. An electrolyser is a unit that converts steam or water into hydrogen and oxygen by using electrical energy.

[0068] Furthermore, in this aspect, the synthesis gas stage may further comprise a third electric heating unit located before the hydrogenation section. The third electric heating unit is configured to heat the first hydrocarbon feed or a mixture of the first hydrocarbon feed and the hydrogen feed to at least 300°C, preferably at least 350°C, before feeding it to the hydrogenation section.

[0069] In this way, a preferred aspect of the synthesis gas stage also includes a hydrogenation section, which is configured to receive a first hydrocarbon feed and a hydrogen feed (optionally in a mixed form) and provide the hydrogenated first hydrocarbon feed to the desulfurization section; preferably, the synthesis gas stage also includes a third electric heating unit, which is configured to heat the first hydrocarbon feed or a mixture of the first hydrocarbon feed and the hydrogen feed, and then feed the first hydrocarbon feed or the mixture of the first hydrocarbon feed and the hydrogen feed to the hydrogenation section.

[0070] Method for producing a first synthesis gas stream

[0071] There is also provided a method of producing a first synthesis gas stream in the synthesis gas stage, the method comprising the steps of:

[0072] a. feeding the first hydrocarbon feed to the pre-reformer section and pre-reforming the first hydrocarbon feed to provide a pre-reformed stream,

[0073] b. feeding the pre-reformed stream to the first electric heating unit and heating the pre-reformed stream,

[0074] c. Feeding the heated pre-reformed stream to the reforming section and reforming it to provide a first synthesis gas stream.

[0075] In a preferred aspect of the method, the pre-reformed stream is heated to at least 400°C, preferably at least 450°C in the first electric heating unit.

[0076] In a preferred aspect of the method, the pre-reformed stream is heated to a temperature below 650°C.

[0077] In a preferred aspect of the process, the synthesis gas stage comprises an autothermal reforming (ATR) section and the process comprises the step of feeding the feed comprising oxidant to the ATR section.

[0078] In a preferred aspect of the method, the synthesis gas stage comprises an autothermal reforming (ATR) section, and further comprises an air separation unit and an air feed, the air separation unit being configured to separate the air feed into at least an oxygen-rich stream, and supplying at least a portion of the oxygen-rich stream to the ATR section as the feed containing the oxidant, the method comprising the steps of feeding the air feed to the air separation unit to provide at least an oxygen-rich stream, and feeding a portion of the oxygen-rich stream to the ATR section.

[0079] equipment

[0080] A hydrogen production plant, an ammonia plant, a methanol plant and a synthetic fuel production plant comprising the synthesis gas stage are provided.

[0081] In a preferred aspect, a plant comprising the syngas stage is provided, wherein the syngas stage comprises an ATR section. In this preferred aspect, the plant operates at a low steam-to-carbon ratio, such as a steam-to-carbon ratio of 0.4 or 0.6, wherein the steam-to-carbon ratio is the steam-to-carbon ratio on a molar basis in the syngas stage (e.g., ATR section). The low steam-to-carbon ratio in the ATR section can reduce energy consumption and reduce plant size because less steam / water is carried in the plant.

[0082] In a preferred aspect, there is also provided an apparatus wherein the ATR section is arranged to operate at a pressure lower than the normally expected ATR section operating pressure (typically 30 barg or higher, e.g. 30-40 barg, such as 37.5 barg). This enables the capture of more carbon, e.g. 97% or more of the carbon in the hydrocarbon feed, without sacrificing energy efficiency, particularly when combined with a steam-to-carbon ratio in the ATR section of 0.4, 0.6 or higher (e.g. 0.8).

[0083] Hydrogen production equipment

[0084] In a preferred aspect, a hydrogen production device comprising the synthesis gas stage is provided, the hydrogen production device further comprising a shift section and a hydrogen purification section, wherein the shift section is configured to receive a first synthesis gas flow from the reforming section and provide a second synthesis gas flow, and wherein the hydrogen purification section is configured to receive the second synthesis gas flow from the shift section and provide a hydrogen-rich flow and a tail gas flow.

[0085] In one aspect, the shift stage comprises a high temperature (HT) shift unit and a low temperature shift unit, the high temperature shift unit being arranged to receive a first syngas stream from the reforming stage and to provide a first shifted syngas stream. Subsequently, the first shifted syngas stream is fed to a low temperature (LT) shift unit for further shifting, thereby providing a second syngas stream, which is shifted according to a water gas shift (WGS) reaction (reaction 3).

[0086] In a preferred aspect, the high temperature (HT) shift unit may comprise a promoted zinc aluminum oxide based high temperature shift catalyst. In this aspect, when the device is in operation, the steam to carbon ratio in the reforming section and the HT shift section is less than 2.6. The advantage of a low steam to carbon ratio in the reforming section and the shift section is that it enables a higher syngas throughput than a high steam to carbon ratio. In addition, a low steam to carbon ratio requires smaller equipment at the front end due to the lower total mass flowing through the equipment.

[0087] In a preferred aspect, the temperature in the high temperature shift step ranges from 300-600°C, such as 300-400°C, such as 350-380°C. In a preferred aspect, the temperature in the low temperature shift step ranges from 180-300°C, such as 200-250°C.

[0088] In one aspect, the purification section is arranged to receive the second synthesis gas stream and to provide a hydrogen product stream and a tail gas stream.

[0089] In one aspect, the purification section comprises a separation unit in which process condensate consisting primarily of water is removed from the product gas.

[0090] In one aspect, the purification section includes a CO2 removal section in which CO2 is separated from the product gas, thereby providing a CO2-rich stream and a CO2-lean stream. In this way, the CO2 in the CO2-rich stream can be captured and stored and / or used for other purposes. Therefore, including a CO2 removal section in a hydrogen production plant can limit the CO2 emissions of the plant.

[0091] In one aspect, the purification section comprises a pressure swing adsorption unit (PSA). In this aspect, the pressure swing adsorption unit provides a hydrogen-rich stream, ie, a hydrogen product stream and a tail gas stream.

[0092] In a preferred aspect, the purification section comprises a separation unit configured to receive a second synthesis gas stream from the conversion section and to provide a process condensate and a first product gas stream, wherein the first product gas stream is sent to a CO2 removal section, in which the CO2 is separated so that the CO2 removal section provides a CO2-rich stream and a second CO2-lean product gas stream, and subsequently the second CO2-lean product gas stream is configured to be fed to a PSA unit, so that the PSA unit is configured to provide a hydrogen product stream and a tail gas stream.

[0093] By providing a synthesis gas stage comprising at least the first electric heating unit, the hydrogen production plant can be arranged to operate in a manner that further reduces CO2 emissions. Typically, preheating of the feed reduces the complexity of the plant layout and improves carbon efficiency. The preheating unit also contributes to a smooth and fast start-up of the plant. Therefore, a method for reducing CO2 emissions from a plant is also provided, the method comprising the following steps: heating a pre-reformed stream in a first electric heating unit, and heating the pre-reformed stream in the first electric heating unit to a temperature of at least 400°C, preferably at least 450°C.

[0094] In order to improve the carbon efficiency of the hydrogen plant, in one aspect, at least a portion of the tail gas stream provided by the hydrogen purification section can be arranged to be recycled to the synthesis gas stage, for example to the inlet of the pre-reformer section or to the reforming section as feed gas. In a preferred aspect, the tail gas can be added to the pre-reformer stream upstream of the ATR section.

[0095] Ammonia equipment

[0096] In one approach, an ammonia plant comprising the synthesis gas stage is provided, the ammonia plant further comprising a purification section followed by an ammonia synthesis loop, and optionally a shift section is arranged upstream of the purification section. In this way, in a preferred aspect, the shift section is arranged to receive a first synthesis gas stream from the reforming section and to provide a shifted first synthesis gas stream. The shifted first synthesis gas stream is then fed to the purification section as feed, the purification section being arranged to also receive a nitrogen-rich stream and to provide a process stream and a tail gas stream. The ammonia synthesis loop is then arranged to receive the process stream and to provide an ammonia product stream.

[0097] In a preferred aspect, the ammonia plant comprises the same shift section and purification section as those included in the hydrogen plant, i.e. the ammonia plant comprises a shift section, a separation unit, a CO2 removal section and a PSA unit. Therefore, the description given for the sections in the description of the hydrogen plant also applies to the ammonia plant.

[0098] Thus, in a preferred aspect, the purification section comprises a separation unit arranged to receive the second synthesis gas stream from the shift section and to provide a process condensate and a first product gas stream, wherein the first product gas stream is sent to a CO2 removal section, in which CO2 is separated, such that the CO2 removal section provides a CO2-rich stream and a second CO2-lean stream, which is then arranged to be fed to a PSA unit, such that the PSA unit is arranged to provide a hydrogen-rich stream and a tail gas stream. In this aspect, the hydrogen-rich stream may be mixed with a nitrogen-rich stream in a preferred H2 / N2 ratio of about 3 to provide a process stream for the ammonia synthesis loop.

[0099] In another aspect, the purification section of the ammonia plant may include one or more conversion sections and a CO2 removal section, followed by a molecular sieve dryer and an N2 scrubbing unit (NWU). After the conversion section and the CO2 removal section, the lean CO2 stream may contain residual CO and CO2, as well as a small amount of CH4, Ar, He and H2O. CO2 and H2O are preferably removed before entering the NWU, otherwise they will freeze at the low operating temperature in the NWU. For example, this can be achieved by adsorption in a molecular sieve dryer, which consists of at least two containers, one container is in operation and the other container is regenerated. Nitrogen can be used as a drying gas for regeneration. The process stream provided by the N2 scrubbing unit is the same as the process stream described in the previous aspect.

[0100] The nitrogen for the NWU may be provided by an air separation unit (ASU) which separates atmospheric air into at least a nitrogen-rich stream and an oxygen-rich stream. In a preferred aspect, the oxygen-rich stream is used in the ATR section and the nitrogen-rich stream is used in the NWU.

[0101] In the NWU, the hydrogen-rich stream is scrubbed in a column with liquid nitrogen to remove CH4, Ar, He and CO. Preferably, the purified synthesis gas contains only Ar and CH4 at the ppm level. After the NWU, a nitrogen-rich stream can be added to the stream to adjust the N2 content to a preferred H2 / N2 ratio of 3, thereby providing a process stream to the ammonia synthesis loop. The ammonia synthesis loop is configured to receive at least a portion of the process stream to provide an ammonia product stream.

[0102] In this way, the ammonia plant comprises a purification section and an ammonia synthesis loop, and optionally also a shift section. The purification section is arranged to receive a first synthesis gas stream from a reforming section to provide a process stream; or, wherein the shift section is arranged to receive a first synthesis gas stream from a reforming section and to provide a shifted first synthesis gas stream. The shifted first synthesis gas stream is fed to the purification section, and the purification section is arranged to provide a process stream, and the ammonia synthesis loop is arranged to receive the process stream and provide an ammonia product stream.

[0103] Methanol equipment

[0104] A methanol plant comprising the synthesis gas stage is also provided.

[0105] In one aspect, the methanol plant also includes a methanol synthesis stage. This stage includes a methanol synthesis section, wherein the first synthesis gas stream from the synthesis gas stage is first converted into a crude methanol stream; followed by a methanol purification section, wherein the crude methanol stream is purified to obtain a methanol product stream. The methanol synthesis stage generates a methanol purge gas stream, which typically contains hydrogen, carbon dioxide, carbon monoxide and methane. Other components such as argon, nitrogen or oxygenates containing two or more carbon atoms may also be present in small amounts.

[0106] Therefore, in a preferred aspect, a methanol device comprising the synthesis gas stage is also provided, the methanol device also comprising a methanol synthesis section and a methanol purification section, wherein the methanol synthesis section is configured to receive a first synthesis gas flow from the reforming section and provide a crude methanol flow, and wherein the methanol purification section is configured to receive a crude methanol flow from the methanol synthesis section and provide a methanol product flow and a purge gas flow.

[0107] In one aspect, at least a portion of the methanol purge gas stream may be fed as additional feed to a synthesis gas stage, such as upstream of an ATR section. In one aspect, the purge gas may be added to a pre-reforming stream upstream of the ATR section. In this way, the purge gas is recycled into the synthesis gas stage, thereby improving the overall carbon efficiency of the equipment. The methanol purge gas stream may be purified before being fed to the synthesis gas stage. Suitably, in order to avoid excessive accumulation of inert components that may be present in the methanol purge gas, only a portion of the methanol purge gas stream may be fed to the synthesis gas stage; while another portion of the methanol purge gas may be discharged and / or used as fuel.

[0108] In particular, in case the plant comprises a methanol synthesis stage, the first synthesis gas stream at the outlet of the synthesis gas stage has a modulus as defined herein in the range of 1.80-2.30; preferably 1.90-2.20. The term "modulus" is defined as:

[0109]

[0110] Synthetic fuel production equipment

[0111] The present invention also provides a synthetic fuel production device comprising the synthesis gas stage described herein, wherein the synthetic fuel production device also includes a synthetic fuel synthesis section (for example, a Fischer-Tropsch synthesis section) and a product purification section, wherein the synthetic fuel synthesis section is configured to receive a first synthesis gas flow from the reforming section and provide a raw product flow, and wherein the product purification section is configured to receive a raw product flow from the synthetic fuel synthesis section and provide a product flow and a tail gas flow.

[0112] Specific embodiments of the present invention

[0113] Figure 1 A first layout of a synthesis gas stage (100) is shown. A first hydrocarbon feed (1), such as a natural gas feed, is fed to a pre-reformer section (20), which is arranged to provide a pre-reformed stream (21). The pre-reformed stream (21) is sent to a first electrical heating unit (40), wherein the pre-reformed stream is heated to at least 400°C, preferably at least 450°C, such as 550°C or more, thereby providing a heated first stream (1a). The heated first stream (1a) is subsequently fed to a reforming section (30), wherein the reforming section (30) is arranged to provide a first synthesis gas stream (31).

[0114] Figure 2A more developed layout of a synthesis gas stage (100) is shown, wherein the reforming section (30) comprises an oxidant section, such as an autothermal reforming (ATR) section. In this layout, a heated first stream (1a) and a feed (91) comprising an oxidant, preferably an oxygen-enriched feed, are fed to a reforming section (30) comprising an ATR section. In the ATR section (30), the heated first stream (1a) and the oxygen-enriched stream (91) react to provide a first synthesis gas stream (31).

[0115] Figure 3 A further developed layout of a synthesis gas stage (100) is shown. In this layout, a first hydrocarbon feed (1) (e.g. a natural gas feed) is optionally mixed with a hydrogen feed (2). The first hydrocarbon feed (1) or mixture is preheated to about 380°C by a third electrical heating unit (80). The preheated stream (3a) is sent to a hydrogenation section (70) in which a hydrogenated first hydrocarbon feed (71) is formed, which is subsequently sent to a desulfurization section (50) to provide a desulfurized first hydrocarbon feed (51). The desulfurized first hydrocarbon feed (51) is heated to about 450°C in a second electrical heating unit (60) and mixed with a steam stream (55) to provide a heated second stream (2a). The heated second stream (2a) is fed to a pre-reformer section (20) which is arranged to provide a pre-reformed stream (21). The pre-reformed stream (21) is sent to a first electric heating unit (40) where it is heated to at least 400°C, preferably at least 450°C, such as at least 550°C, thereby providing a heated first stream (1a). The heated first stream (1a) is subsequently fed to a reforming section (30), preferably an oxidant section, such as an ATR section.

[0116] exist Figure 3 In the reforming section (30), in addition to receiving the heated first stream (1a), the reforming section (30) is also arranged to receive a feed (91) comprising an oxidant (preferably an oxygen-enriched feed), which is provided by an air separation unit (90). Thus, the air separation unit (90) is arranged to receive an air feed (4) and is arranged to separate the air feed (4) into at least an oxygen-enriched stream (91) to supply at least a portion of the oxygen-enriched stream (91) to the reforming section (30). In the reforming section (30), the heated first stream (1a) and the oxygen-enriched stream (91) react to provide a first synthesis gas stream (31).

[0117] Figure 4 The layout of a development of a hydrogen plant (500) comprising a syngas stage (100) and a synthesis stage (200) is shown. Figure 3 The description of the synthesis gas stage (100) in the description of Figure 4The synthesis gas stage (100) is thus arranged to provide a first synthesis gas stream (31) from a reforming section (30), wherein the reforming section (30) is preferably an ATR section. A first waste heat boiler (110) is arranged downstream of the reforming unit (30) and provides an internal steam feed (111) to a steam drum (120).

[0118] The steam drum (120) is arranged to dry the steam by separating the liquid water and to provide a first steam flow (121) as required. The steam drum is supplied with boiler feed water (not shown) corresponding to the steam production and boiler water discharge (not shown).

[0119] In the embodiment shown, a portion of the superheated steam stream is also mixed with the first synthesis gas stream (31) downstream of the first waste heat boiler. A high temperature shift (HT) reactor (210) receives the first synthesis gas stream (31) downstream of the first waste heat boiler (110) and provides a first shifted synthesis gas stream (211). A steam superheater (220) is disposed downstream of the HT shift reactor and superheats the first steam stream (121) from the steam drum (120) by heat exchange with the first shifted synthesis gas stream (211) from the HT shift reactor (210).

[0120] Downstream of the superheater (220), the shifted synthesis gas stream is then fed to a low temperature (LT) shift reactor (240) for further shifting. As shown in the figure, a second waste heat boiler (230) is located between the HT shift reactor and the LT shift reactor, and generates a second internal steam feed (231) for the steam drum (120) by heat exchange with the shifted synthesis gas stream downstream of the steam superheater (220) through the boiler water flow from the steam drum (120).

[0121] like Figure 4 As shown, the steam stream (123) is mixed with the oxygen-rich stream (91). After the LT shift, the product gas is sent to a separator (250) where a process condensate 252 (mainly containing water) is removed. Thereafter, the product gas (251) is sent to a CO2 removal section 260 where CO2 is removed in the form of a CO2-rich stream (262). The product gas is then sent to a pressure swing adsorption (PSA) unit (270) to separate a hydrogen stream (271) and a tail gas stream (272), which can be output as fuel. Example

[0122] Examples 1-4 show that based on Figure 4 The calculation results of various parameters of the layout.

[0123]

[0124]

[0125] Example 1 does not have an electric heater at the ATR inlet. Example 2 and Example 3 differ in the ATR inlet temperature. It can be seen that these three examples achieve zero carbon emissions during the preheating process. Example 4 is the same as Example 3, but the electric heater is replaced with a flame heater. This example shows that significant CO2 emissions are generated during the preheating process.

[0126] The invention has been described with reference to various aspects and drawings. However, a person skilled in the art will be able to select and combine various aspects within the scope of the invention defined by the appended claims. All documents cited herein are incorporated herein by reference.

Claims

1. A synthesis gas stage (100), the stage (100) comprising: - a first hydrocarbon feed (1), a pre-reformer section (20) arranged to receive said first hydrocarbon feed (1) and to provide a pre-reformed stream (21), a reforming section (30) arranged to receive the pre-reformed stream (21) and to provide a first synthesis gas stream (31), The synthesis gas stage (100) comprises a first electric heating unit (40) located between the pre-reformer section (20) and the reforming section (30), the first electric heating unit being arranged to heat the pre-reformed stream (21) to at least 400°C, preferably at least 450°C, before feeding it to the reforming section (30).

2. The synthesis gas stage (100) according to claim 1, wherein the first electrical heating unit (40) is arranged to heat the pre-reformed stream (21) to a temperature below 650°C.

3. A synthesis gas stage (100) according to any of the preceding claims, wherein the synthesis gas stage (100) does not comprise a fired heater, in particular wherein the stage does not comprise a fired heater arranged to heat the pre-reformed stream (21) before feeding it to the reforming section (30).

4. The synthesis gas stage (100) according to any of the preceding claims, further comprising a desulfurization section (50), which is configured to receive the first hydrocarbon feed (1) and provide a desulfurized first hydrocarbon feed (51), and the synthesis gas stage (100) further comprises a second electric heating unit (60), which is configured to heat the desulfurized first hydrocarbon feed (51) and then feed the desulfurized first hydrocarbon feed (51) to the pre-reformer section (20).

5. The synthesis gas stage (100) according to claim 4 further comprises a hydrogenation section (70), which is configured to receive an optionally mixed first hydrocarbon feed (1) and a hydrogen feed (2), and to provide a hydrogenated first hydrocarbon feed (71) to the desulfurization section (50), preferably, wherein the synthesis gas stage (100) further comprises a third electric heating unit (80), which is configured to heat the first hydrocarbon feed (1) or a mixture of the first hydrocarbon feed (1) and the hydrogen feed (2), and then feed the first hydrocarbon feed (1) or the mixture of the first hydrocarbon feed (1) and the hydrogen feed (2) to the hydrogenation section (70).

6. A synthesis gas stage (100) according to any of the preceding claims, wherein the reforming section comprises at least one of: an autothermal reforming (ATR) section, a reverse water gas shift (RWGS) section, a steam methane reformer (SMR) section, a steam methane reformer-b (SMR-b) section and / or a convective reformer (HTCR) section, optionally wherein the reverse water gas shift section is electrically heated.

7. A synthesis gas stage (100) according to claim 6, wherein the reforming section comprises an autothermal reforming (ATR) section, and the ATR section is arranged to receive a feed (91) comprising an oxidant.

8. The synthesis gas stage (100) according to claim 7, further comprising an air separation unit (90) and an air feed (4), wherein the air separation unit (90) is configured to separate the air feed (4) into at least an oxygen-rich stream (91), and to supply at least a portion of the oxygen-rich stream (91) to the ATR section (30) as a feed (91) comprising an oxidant.

9. A method for producing a first synthesis gas stream (31) in a synthesis gas stage (100) according to any one of the preceding claims, the method comprising the steps of: a. feeding the first hydrocarbon feed (1) to the pre-reformer section (20), and pre-reforming the first hydrocarbon feed (1) to provide a pre-reformed stream (21); b. feeding the pre-reformed stream (21) to the first electric heating unit (40) and heating the pre-reformed stream (21); c. Feeding the heated pre-reformed stream (21) to the reforming section (30) and reforming it to provide a first synthesis gas stream (31).

10. The method according to claim 9, wherein the pre-reformed stream (21) is heated in the first electric heating unit (40) to a temperature of at least 400°C, preferably at least 450°C.

11. A method according to any one of claims 9-10, wherein the synthesis gas stage (100) comprises an autothermal reforming (ATR) section, and the method comprises the step of feeding a feed (91) comprising the oxidant to the ATR section.

12. A method according to any one of claims 9 to 11, wherein the synthesis gas stage (100) comprises an autothermal reforming (ATR) section and further comprises an air separation unit (90) and an air feed (4), the air separation unit (90) being arranged to separate the air feed (4) into at least an oxygen-rich stream (91) and to supply at least a portion of the oxygen-rich stream (91) as the feed (91) comprising the oxidant to the ATR section (30), the method comprising the steps of: The air feed (4) is fed to the air separation unit (90) to provide at least an oxygen-rich stream (91), and a portion of the oxygen-rich stream (91) is fed to the ATR section.

13. A hydrogen production device (500), comprising a synthesis gas stage (100) according to any one of claims 1 to 8, the hydrogen production device (500) further comprising a conversion section (210-240) and a hydrogen purification section (250-270), wherein the conversion section (210-240) is configured to receive a first synthesis gas flow (31) from the reforming section (30) and provide a second synthesis gas flow (241), and wherein the hydrogen purification section (250-270) is configured to receive a second synthesis gas flow (241) from the conversion section (210-240) and provide a hydrogen-rich flow (271) and a tail gas flow (272).

14. An ammonia device, comprising a synthesis gas stage (100) according to any one of claims 1 to 8, the ammonia device also comprising a purification section and an ammonia synthesis loop, optionally further comprising a shift section, wherein the purification section is configured to receive a first synthesis gas stream from the reforming section to provide a process stream; or, wherein the shift section is configured to receive a first synthesis gas stream from the reforming section and to provide a shifted first synthesis gas stream, and wherein the shifted first synthesis gas stream is fed to the purification section, and the purification section is configured to provide a process stream, and wherein the ammonia synthesis loop is configured to receive the process stream and provide an ammonia product stream.

15. A methanol device, comprising a synthesis gas stage (100) according to any one of claims 1 to 8, the methanol device also comprising a methanol synthesis section and a methanol purification section, wherein the methanol synthesis section is configured to receive a first synthesis gas flow from the reforming section and provide a crude methanol flow, and wherein the methanol purification section is configured to receive a crude methanol flow from the methanol synthesis section and provide a methanol product flow and a tail gas flow.

16. A synthetic fuel production device, comprising a synthesis gas stage (100) according to claim 7 or 8, and the synthetic fuel production device also includes a synthetic fuel synthesis section such as a Fischer-Tropsch synthesis section and a product purification section, wherein the synthetic fuel synthesis section is configured to receive a first synthesis gas flow from the reforming section and provide a raw product flow, and wherein the product purification section is configured to receive a raw product flow from the synthetic fuel synthesis section and provide a product flow and a tail gas flow.

17. A method for reducing CO2 emissions in a hydrogen plant (500) according to claim 13, an ammonia plant according to claim 14, a methanol plant according to claim 15 or a synthetic fuel production plant according to claim 16, the method comprising the following steps: The pre-reformed stream (21) is heated in the first electric heating unit (40) and the pre-reformed stream (21) is heated to a temperature of at least 400°C, preferably at least 450°C in the first electric heating unit (40).

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