CN119894815A

CN119894815A - ATR reforming

Info

Publication number: CN119894815A
Application number: CN202380066614.7A
Authority: CN
Inventors: A·萨海; K·阿斯伯格-彼得森; T·S·克里斯滕森; S·S·克里斯坦森
Original assignee: Haldor Topsoe AS
Current assignee: Topsoe AS
Priority date: 2022-09-16
Filing date: 2023-09-15
Publication date: 2025-04-25
Also published as: AU2023342655A1; CA3267364A1; EP4587380A1; WO2024056870A1; AR130501A1

Abstract

The invention relates to a synthesis gas stage, wherein an electric heating unit is located between a pre-reformer section and an ATR section. A first electric heating unit is arranged to heat the pre-reformed stream to at least 400°C before feeding it to the ATR section. The invention also relates to a method for producing a first synthesis gas stream, a hydrogen plant (which can be used in hydrogen, ammonia, methanol and synthetic fuel production plants) and a method for reducing _CO2 emissions from a hydrogen plant.

Description

ATR reforming

Technical Field

The present invention relates to a synthesis gas stage wherein an electrical heating unit is located between the pre-reformer section and the reforming section. The first electrical heating unit is configured to heat the pre-reformed stream to at least 400 ℃ before feeding it to the reforming section. In this way, one or more fired heaters may be avoided. The invention also relates to a method of producing a first synthesis gas stream and to a production plant, such as a hydrogen plant, an ammonia plant, a methanol plant and a synthetic fuel production plant comprising said synthesis gas stage, and to a method for reducing CO ₂ emissions from said plant.

Background

In order to optimize the production of hydrogen plants, great efforts are made to increase the overall energy efficiency and reduce capital costs. The need for more cost effective hydrogen production has motivated the development of technology and catalysts for large scale hydrogen production units to benefit from economies of scale. Efforts are also being made to reduce the greenhouse gas emissions of such devices.

There would be a significant advantage in reducing CO ₂ emissions (among other things) from a hydrogen plant.

WO2022038089 describes an apparatus for producing a hydrogen rich stream from a hydrocarbon feed.

Disclosure of Invention

It is an object of the present invention to reduce the consumption of hydrocarbon feed and fuel in hydrogen plants and/or processes, thereby improving energy efficiency. At the same time, another object is to reduce CO ₂ emissions in hydrogen plants and/or processes. The carbon footprint of the device may thus be significantly reduced.

The present invention achieves these and other objects.

Thus, in a first aspect, there is provided a synthesis gas stage, the stage comprising:

-a first hydrocarbon feed to the reactor of the reactor,

A pre-reformer section arranged to receive the first hydrocarbon feed and to provide a pre-reformed stream,

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

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

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

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

b. Feeding the pre-reformed stream to the first electrical heating unit and heating the pre-reformed stream;

c. the heated pre-reformed stream is fed to the reforming section and reformed to provide a first synthesis gas stream.

Hydrogen plants, ammonia plants, methanol plants, and synthetic fuel production plants including the synthesis gas stage described herein are also provided.

The introduction of the electric heater enables a smooth start-up of the device. The electric heater powered by renewable energy sources improves the overall carbon efficiency of the device.

Further details of the invention are given in the following description, drawings, aspects and dependent claims.

Drawings

The present technology is illustrated by the following schematic diagram, wherein:

FIG. 1 shows a simplified layout of one aspect of the system of the present invention.

Figure 2 shows a further developed layout of the system of the present invention.

Figure 3 shows a further developed layout of the system of the present invention.

FIG. 4 shows a developed layout of the system of the present invention including a developed layout of a hydrogen plant.

Detailed Description

Any given percentage of gas content is% by volume unless otherwise indicated. All feeds were preheated as needed.

For the avoidance of doubt, the term "feed" refers to a device, such as a pipe, conduit or the like, that supplies the gas to an appropriate section, reactor or unit.

A "section" includes one or more "units" that change the chemical composition of the feed, and may also include elements that do not change the chemical composition of the feed or stream, such as heat exchangers, mixers, or compressors.

Similarly, a "phase" includes one or more segments.

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

In a first aspect, a syngas stage is provided. The output of this stage is a stream of synthesis gas (SYNTHESIS GAS), for example comprising CO, H ₂、H₂O、CO₂、CH₄ and mixtures thereof.

Synthesis gas stage

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

-a first hydrocarbon feed to the reactor of the reactor,

Wherein the synthesis gas stage comprises a first electrical heating unit located between the pre-reformer stage and the reforming stage, the first electrical heating unit being arranged to heat the pre-reformed stream to at least 400 ℃, preferably at least 450 ℃, before feeding it to the reforming stage.

A first hydrocarbon feed is provided. The first hydrocarbon feed suitably comprises a major portion of methane, for example 80% or more, preferably 90% or more 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.

A pre-reformer section is configured to receive the first hydrocarbon feed and provide a pre-reformed stream. Prereforming is the process of steam reforming methane and heavier hydrocarbons and methanation of the reformate of the heavier hydrocarbons. The pre-reformer section may comprise an adiabatic pre-reformer filled with a catalyst of high nickel content and a main steam reformer. The adiabatic prereformer is typically located upstream of the main steam reformer. Steam may be added to the hydrocarbon-containing stream upstream of the pre-reforming stage. The pre-reformed stream provided contains CO ₂、CH₄、H₂ O and H ₂, as well as typically smaller amounts of CO and other possible components.

In the prereformer, all higher hydrocarbons can be converted to carbon oxides and methane, but the prereformer is also advantageous for light hydrocarbons. The provision of a prereformer may provide a number of benefits including reducing the required O ₂ consumption in the ATR and allowing the inlet temperature to the ATR to be increased, since the risk of cracking due to preheating is minimised. In addition, the prereformer may provide effective sulfur protection such that the feed gas to the ATR and downstream systems is nearly sulfur free.

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

The reforming section includes 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 arranged to receive a feed comprising an oxidant.

The ATR section may comprise one or more ATR reactors such that the core portion of the ATR section is one or more ATR reactors. ATR reactors typically comprise a burner, a combustion chamber and a catalyst bed contained within a refractory lined pressure shell. In an ATR reactor, hydrocarbons are partially combusted with a sub-stoichiometric amount of an oxidant, such as oxygen, followed by steam reforming of the partially combusted hydrocarbons in a fixed bed of a steam reforming catalyst (reactions 1 and 2).

Due to the high temperature, some degree of steam reforming also occurs in the combustion chamber. The steam reforming reaction is accompanied by a water gas shift reaction. Typically, at the reactor outlet, the gas is at or near equilibrium with respect to the steam reforming and water gas shift reactions. More details and complete description about 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").

Because the ATR section requires a sub-stoichiometric amount of oxidant (e.g., oxygen) to effect partial combustion of the hydrocarbons, a feed comprising the oxidant is provided to the ATR section. Suitably, the oxidant feed consists essentially of oxygen. The oxidant feed of O ₂ is preferably "oxygen-rich" meaning that the major component of the feed is O ₂, i.e., more than 75%, such as more than 90% or more than 95%, even more than 99% of the feed is O ₂. The oxidant feed may also contain other components such as nitrogen, argon, CO ₂, 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. The source of oxygen may also be at least one cell unit. Part or all of the oxidant feed to O ₂ may come from at least one electrolyzer that uses electrical energy to convert steam or water into hydrogen and oxygen. Upstream of the ATR section, steam may be added to the oxidant feed comprising oxygen.

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

In another preferred aspect, the synthesis gas stage comprises a 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-enriched stream and to supply at least a portion of the oxygen-enriched stream to the ATR section as a feed comprising an oxidant. In this respect, it is noted that since the reforming section receives a pre-reformed stream, which stream comprises primarily CO ₂、CH₄、H₂ O and H ₂, the amount of O ₂ consumption required in the ATR reactor is reduced compared to the alternative in which the reforming section receives a hydrocarbon feed that has not been pre-reformed.

Typically, the effluent gas stream from the ATR reactor, i.e. the first synthesis gas stream, has a temperature of 900-1100 ℃. Synthesis gas typically comprises hydrogen, carbon monoxide, carbon dioxide and steam. Other components such as methane, nitrogen and argon may also be present, but are typically present in minor amounts. The ATR reactor is operated at a pressure of from 5 to 100 bar, more preferably from 15 to 60 bar.

The synthesis gas stage further comprises a first electrical heating unit located between the pre-reformer section and the reforming section. The first electrical heating unit is arranged to heat the pre-reformed stream to at least 400 ℃, preferably at least 450 ℃, 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 due to preheating is minimized. Essentially, the synthesis gas stage is arranged in such a way that there is no temperature change between the electric heating unit and the reforming section.

In a conventional synthesis gas stage, at least one fired heater is typically provided to preheat the pre-reformed stream upstream of the inlet of the reforming section. To reduce the carbon emissions of the fired heater, the inlet temperature of the reforming section is maintained at a low level, for example below 450 ℃, such as 400 ℃. To avoid carbon emissions entirely, fired heaters may also be eliminated. However, the removal of the fired heater complicates operation and increases the difficulty of starting. Thus, the synthesis gas stage is provided with an electric heater to heat the pre-reformed gas at the inlet of the reforming stage (e.g. the inlet of the ATR stage). The combination of an electric heater with renewable power also does not have an effect on the carbon emissions of the synthesis gas stage or the plant comprising the synthesis gas stage. In this way, the use of renewable electric power electric heaters allows the provision of green energy sources to promote production, such as H ₂ production (for example in the case of the synthesis gas stage being contained in a hydrogen plant), for a given amount of O ₂, without increasing CO ₂ 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, where heating the pre-reformed stream to at least 450 ℃, such as 550 ℃ or higher, will reduce oxygen consumption at the same synthesis gas generation capacity, or increase synthesis gas generation capacity at a given oxygen flow rate, without any carbon emissions.

In conventional plants, a fired heater is typically provided to preheat the pre-reformed stream entering the ATR. To reduce the carbon emissions of the fired heater, the inlet temperature of the ATR is maintained at a low level, for example below 450 ℃, such as 400 ℃. To avoid carbon emissions entirely, the fired heater can also be eliminated entirely. However, the removal of the fired heater can make the operation of the device somewhat complicated and also increase the difficulty of starting. The apparatus of the present invention is therefore arranged with an electric heater to heat the pre-reformed gas entering the ATR. The combination of the electric heater with renewable power also does not have an impact on the carbon emissions of the device. Heating the pre-reformed gas to at least 450 ℃ (e.g., 550 ℃ or higher) will reduce oxygen consumption at the same syngas generation capacity, or increase syngas generation capacity at a given oxygen flow rate, without any carbon emissions.

Thus, in a preferred aspect, the synthesis gas stage comprises a first electrical heating unit, wherein the first electrical heating unit is arranged to heat the pre-reformed stream to a temperature below 650 ℃.

In other aspects, the reforming section within the synthesis gas stage can comprise 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 a resistive heating 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 includes at least one e-RWGS reactor. In the e-RWGS reactor, selective or non-selective RWGS can be carried out, where "selective RWGS" means that only the reverse water gas shift reaction according to reaction 3 occurs,

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

In a preferred aspect and as one example, the reforming section includes non-selective RWGS. The RWGS reaction (3) is an endothermic process that requires a large 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 methanation is an exothermic reaction. Since the CO reduction reaction is also exothermic, the temperature increase caused by 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 of the CO reduction reaction at all. This particular level will depend on the particular reactant concentration, inlet temperature and pressure, but will typically be in the range 600-800 ℃, above which there is no possibility that CO reduction will occur. Thus, the e-RWGS reactor allows for increasing the temperature within the reactor from a relatively low inlet temperature (e.g., 400-600 ℃) to a higher product gas temperature across the entire reactor.

Thus, in a preferred aspect, the reforming section within the synthesis gas stage comprises an e-RWGS section and a first electrical heating unit located between the pre-reformer section and the reforming section, the first electrical heating unit being arranged to heat the pre-reformed stream to at least 400 ℃, preferably at least 450 ℃, before feeding it to the reforming section.

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 an e-RWGS section. In a preferred aspect, the SMR section is electrically heated such that it is an e-SMR section. The e-SMR section includes at least one SMR reactor in which methane is typically heated by steam 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 electrical heating unit is 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 ℃, preferably at least 450 ℃, before feeding it to the reforming section.

In another aspect, the reforming section comprises a convection reforming section, e.g. HaldorA convective reforming (HTCR) section. In this aspect, the SMR and ATR reforming processes are integrated such that the conversion of hydrocarbons and steam to hydrogen and carbon oxides proceeds entirely autothermally, avoiding any external fuel combustion heating. Thus, the HTCR section includes an integrated reactor that is designed to include a primary reformer zone and a secondary reformer zone. The primary reformer zone receives the pre-reformed stream and provides an SMR reformate effluent that passes through a catalyst bed into a space at the feed end of the secondary reformer zone where a preheated oxidant (e.g., oxygen) containing feed is introduced such 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 (SHELL SIDE) of the primary reforming zone, thereby providing the required heat for the endothermic SMR reforming reactions that occur within the catalyst-containing reactor tubes of the primary reformer zone. Like the 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, whereby by providing a first electrical heating unit located between the pre-reformer section and the reforming section, it is provided in a preferred aspect to heat the pre-reformed stream to at least 400 ℃, preferably at least 450 ℃, before feeding it to the reforming section.

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

Desulfurization section

In one aspect, the syngas stage further comprises a desulfurization section configured to receive the first hydrocarbon feed and provide a desulfurized first hydrocarbon feed. Sulfur may be present in the hydrocarbon feed in the form of sulfides, however, sulfur is not preferred in the stream entering the reforming section because the presence of sulfur typically results in catalyst contamination, such as the formation of carbon deposits on the catalyst surface. Thus, in a preferred aspect, the synthesis gas stage further comprises a desulfurization section arranged upstream of the reforming section, more preferably upstream of the pre-reformer section.

In aspects where the syngas stage includes a desulfurization section, the syngas stage may further include a second electrical heating unit located between the desulfurization section and the pre-reformer section. The second electrical heating unit is configured to heat the desulfurized first hydrocarbon feed to at least 400 ℃, preferably at least 450 ℃, prior to feeding it to the pre-reformer section.

Thus, in a preferred aspect, the synthesis gas stage further comprises a desulfurization section arranged to receive the first hydrocarbon feed and to provide a desulfurized first hydrocarbon feed, and a second electrical heating unit arranged to heat the desulfurized first hydrocarbon feed prior to feeding the desulfurized first hydrocarbon feed to the pre-reformer section.

Hydrogenation section

In one aspect, the synthesis gas stage includes a desulfurization section, which may further include a hydrogenation section configured 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.

In this aspect, the hydrogen feed is suitably "hydrogen-rich" meaning that the major portion of the feed is hydrogen, i.e. 75% or more, for example 85% or more, preferably 90% or more, more preferably 95% or more, even more preferably 99% or more of the feed is hydrogen. Part or all of the hydrogen feed may come from at least one electrolyzer. An electrolyzer refers to a unit that converts steam or water into hydrogen and oxygen by using electric energy.

Further in this aspect, the synthesis gas stage may further comprise a third electrical heating unit located before the hydrogenation section. The third electrical heating unit is arranged to heat the first hydrocarbon feed or the mixture of the first hydrocarbon feed and the hydrogen feed to at least 300 ℃, preferably at least 350 ℃, before feeding it to the hydrogenation section.

In this manner, a preferred aspect of the synthesis gas stage further comprises a hydrogenation section arranged to receive the first hydrocarbon feed and the hydrogen feed (optionally in a mixed form) and to provide the hydrogenated first hydrocarbon feed to the desulfurization section, preferably wherein the synthesis gas stage further comprises a third electrical heating unit arranged to heat the first hydrocarbon feed or the 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.

Method for producing a first synthesis gas stream

a. Feeding the first hydrocarbon feed to the pre-reformer stage and pre-reforming the first hydrocarbon feed to provide a pre-reformed stream,

B. feeding the pre-reformed stream to the first electric heating unit and heating the pre-reformed stream,

In a preferred aspect of the method, the pre-reformed stream is heated to at least 400 ℃, preferably at least 450 ℃, in the first electrical heating unit.

In a preferred aspect of the process, the pre-reformed stream is heated to a temperature below 650 ℃.

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.

In a preferred aspect of the process, the synthesis gas stage comprises an autothermal reforming (ATR) section and further comprises an air separation unit arranged to separate the air feed into at least an oxygen-enriched stream and to supply at least a portion of the oxygen-enriched stream as the oxidant-containing feed to the ATR section, and an air feed, the process comprising the steps of feeding the air feed to the air separation unit to provide at least an oxygen-enriched stream and feeding a portion of the oxygen-enriched stream to the ATR section.

Apparatus and method for controlling the operation of a device

Hydrogen plants, ammonia plants, methanol plants, and synthetic fuel production plants are provided that include the synthesis gas stage.

In a preferred aspect, there is provided an apparatus comprising the synthesis gas stage, wherein the synthesis gas stage comprises an ATR section. In this preferred aspect, the apparatus is operated at a low steam to carbon ratio, for example a steam to carbon ratio of 0.4 or 0.6, wherein the steam to carbon ratio is based on the molar ratio in the synthesis gas stage (e.g. ATR stage). The low steam carbon ratio in the ATR section can reduce energy consumption and reduce plant size because less steam/water is carried in the plant.

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

Hydrogen production plant

In a preferred aspect, a hydrogen plant is provided that includes the synthesis gas stage, the hydrogen plant further including a shift section and a hydrogen purification section, wherein the shift section is configured to receive a first synthesis gas stream from a reforming section and provide a second synthesis gas stream, and wherein the hydrogen purification section is configured to receive the second synthesis gas stream from the shift section and provide a hydrogen-rich stream and a tail gas stream.

In one aspect, the shift section includes a High Temperature (HT) shift unit configured to receive a first syngas stream from the reforming section and provide a first shifted syngas stream and a low temperature shift unit. The first shifted syngas stream is then fed to a Low Temperature (LT) shift unit for further shifting to provide a second syngas stream that is shifted according to a Water Gas Shift (WGS) reaction (reaction 3).

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, the steam to carbon ratio in the reforming section and the HT shift section is less than 2.6 when the apparatus is in operation. The advantage of low steam to carbon ratio in the reforming section and shift section is that it enables higher syngas throughput than high steam to carbon ratio. In addition, low steam carbon is smaller than the equipment required at the front end due to the lower total mass flowing through the equipment.

In a preferred aspect, the temperature in the high temperature shift step is in the range 300-600 ℃, e.g. 300-400 ℃, e.g. 350-380 ℃. In a preferred aspect, the temperature in the low temperature shift step is in the range of 180-300 ℃, e.g. 200-250 ℃.

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

In one aspect, the purification section includes a separation unit in which process condensate consisting essentially of water is removed from the product gas.

In one aspect, the purification section includes a CO ₂ removal section in which CO ₂ is separated from the product gas, providing a CO-rich ₂ stream and a CO-lean ₂ stream. In this way, CO ₂ in the CO ₂ -rich stream may be captured and stored and/or used for other purposes. Thus, the inclusion of a CO ₂ removal section in the hydrogen manufacturing facility can limit the CO ₂ emissions of the facility.

In one aspect, the purification section includes a pressure swing adsorption unit (PSA). In this aspect, the pressure swing adsorption unit provides a hydrogen-rich stream, i.e., a hydrogen product stream and a tail gas stream.

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 CO ₂ removal section in which CO ₂ is separated such that the CO ₂ removal section provides a CO-rich ₂ stream and a second CO-lean ₂ product gas stream, and then the second CO-lean ₂ product gas stream is arranged to be fed to the PSA unit such that the PSA unit is arranged to provide a hydrogen product stream and an offgas stream.

By providing a synthesis gas stage comprising at least said first electrical heating unit, the hydrogen plant may be arranged to operate in a manner that further reduces CO ₂ emissions. In general, preheating of the feed reduces complexity of the plant layout and improves carbon efficiency. The preheating unit also contributes to a smooth and quick start-up of the device. Accordingly, there is also provided a method of reducing plant CO ₂ emissions, the method comprising the steps of heating a pre-reformed stream in a first electrical heating unit and heating the pre-reformed stream in the first electrical heating unit to a temperature of at least 400 ℃, preferably at least 450 ℃.

To increase 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 may be configured to be recycled to the synthesis gas stage, for example as feed gas to the inlet of the pre-reformer section or to the reforming section. In a preferred aspect, the tail gas may be added to the pre-heavy stream upstream of the ATR section.

Ammonia plant

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

In a preferred aspect, the ammonia plant comprises the same shift and purification sections as included in the hydrogen plant, i.e., the ammonia plant comprises a shift section, a separation unit, a CO ₂ removal section, and a PSA unit. Thus, the description given for the section in the description of the hydrogen production apparatus applies equally to the ammonia apparatus.

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 provide a process condensate and a first product gas stream, wherein the first product gas stream is sent to a CO ₂ removal section in which CO ₂ is separated such that the CO ₂ removal section provides a CO-rich ₂ stream and a second CO-lean ₂ stream, and subsequently the second CO-lean ₂ stream is 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 the nitrogen-rich stream in a preferred H ₂/N₂ ratio of about 3 to provide a process stream for the ammonia synthesis loop.

In another aspect, the purification section of the ammonia plant may include one or more shift sections and a CO ₂ removal section followed by a molecular sieve dryer and an N ₂ wash unit (NWU). After the shift and CO ₂ removal sections, the CO-lean ₂ stream may contain residual CO and CO ₂, as well as small amounts of CH ₄, ar, he and H ₂O.CO₂ and H ₂ O, which would otherwise freeze at low operating temperatures within NWU, are preferably removed prior to entering NWU. This can be achieved, for example, by adsorption in a molecular sieve dryer consisting of at least two vessels, one vessel being regenerated while in operation. Nitrogen may be used as the regenerated dry gas. The process stream provided by the N ₂ wash unit is the same as described in the previous aspect.

Nitrogen for NWU may be provided by an Air Separation Unit (ASU) that separates atmospheric air into at least a nitrogen-rich stream and an oxygen-rich stream. In a preferred aspect, the oxygen-enriched stream is used in the ATR section and the nitrogen-enriched stream is used in NWU.

In NWU, the hydrogen-rich stream is scrubbed within the column by liquid nitrogen to remove CH ₄, ar, he and CO. Preferably, the purified synthesis gas contains only ppm levels of Ar and CH ₄. After NWU, a nitrogen-rich stream may be added to the stream to adjust the N ₂ content to a preferred H ₂/N₂ ratio of 3 to provide 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.

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 configured to receive the first syngas stream from the reforming section to provide a process stream, or wherein the shift section is configured to receive the first syngas stream from the reforming section and provide a shifted first syngas stream. The shifted first synthesis gas stream is fed to a purification section, and the purification section is configured to provide a process stream, and the ammonia synthesis loop is configured to receive the process stream and provide an ammonia product stream.

Methanol plant

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

In one aspect, the methanol plant further comprises a methanol synthesis stage. This stage includes a methanol synthesis section in which the first synthesis gas stream from the synthesis gas stage is first converted to a crude methanol stream, followed by a methanol purification section in which the crude methanol stream is purified to obtain a methanol product stream. The methanol synthesis stage produces a methanol purge gas (purge gas) stream that typically contains hydrogen, carbon dioxide, carbon monoxide and methane. Other components such as argon, nitrogen or oxygen-containing compounds containing two or more carbon atoms may also be present in minor amounts.

Thus, in a preferred aspect there is also provided a methanol plant comprising the synthesis gas stage, the methanol plant further comprising a methanol synthesis section and a methanol purification section, wherein the methanol synthesis section is arranged to receive the first synthesis gas stream from the reforming section and to provide a crude methanol stream, and wherein the methanol purification section is arranged to receive the crude methanol stream from the methanol synthesis section and to provide a methanol product stream and a purge gas stream.

In one aspect, at least a portion of the methanol purge stream may be fed as additional feed to the synthesis gas stage, e.g., upstream of the ATR stage. In one aspect, purge gas may be added to the pre-reformed stream upstream of the ATR section. In this way, the purge gas is recycled to the synthesis gas stage, thereby improving the overall carbon efficiency of the plant. The methanol purge stream may be purified prior to being fed to the synthesis gas stage. Suitably, 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 vented and/or used as fuel.

Particularly where the apparatus 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 1.80 to 2.30, preferably 1.90 to 2.20. The term modulus is defined as:

Synthetic fuel production equipment

The present invention also provides a synthetic fuel production plant comprising a synthesis gas stage as described herein, the plant further comprising a synthetic fuel synthesis section (e.g. comprising a fischer-tropsch synthesis section) and a product purification section, wherein the synthetic fuel synthesis section is arranged to receive a first synthesis gas stream from the reforming section and to provide a crude product stream, and wherein the product purification section is arranged to receive the crude product stream from the synthetic fuel synthesis section and to provide a product stream and an off-gas stream.

Detailed description of the invention

FIG. 1 shows a first layout of a syngas stage (100). A first hydrocarbon feed (1) (e.g., a natural gas feed) is fed to a pre-reformer section (20) configured to provide a pre-reformed stream (21). The pre-reformed stream (21) is sent to a first electrical heating unit (40) where it is heated to at least 400 ℃, preferably at least 450 ℃, such as 550 ℃ or higher, thereby providing a heated first stream (1 a). The heated first stream (1 a) is then fed to a reforming section (30), wherein the reforming section (30) is arranged to provide a first synthesis gas stream (31).

Fig. 2 shows a more developed layout of the synthesis gas stage (100) wherein the reforming section (30) comprises an oxidant-requiring section, such as an autothermal reforming (ATR) section. In this arrangement, a heated first stream (1 a) and a feed (91) comprising an oxidant, preferably an oxygen-rich feed, are fed to a reforming section (30) comprising an ATR section. In the ATR section (30), the heated first stream (1 a) and the oxygen-enriched stream (91) react to provide a first synthesis gas stream (31).

Fig. 3 shows a further developed layout of the synthesis gas stage (100). In this arrangement, 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 ℃ by a third electrical heating unit (80). The preheat stream (3 a) is passed to a hydrogenation section (70) in which a hydrogenated first hydrocarbon feed (71) is formed, which is then passed to a desulfurization section (50) to provide a desulfurized first hydrocarbon feed (51). The desulfurized first hydrocarbon feed (51) is heated to about 450 ℃ in a second electrical heating unit (60) and is mixed with a vapor stream (55) to provide a heated second stream (2 a). The heated second stream (2 a) is fed to a pre-reformer section (20) arranged to provide a pre-reformed stream (21). The pre-reformed stream (21) is sent to a first electrical heating unit (40) in which the pre-reformed stream is heated to at least 400 ℃, preferably at least 450 ℃, such as at least 550 ℃, thereby providing a heated first stream (1 a). The heated first stream (1 a) is then fed to a reforming section (30), preferably an oxygenate section, such as an ATR section.

In fig. 3, the reforming section (30) is arranged to receive, in addition to the heated first stream (1 a), a feed (91), preferably an oxygen-enriched feed, comprising an oxidant, which feed is provided by an air separation unit (90). Thus, the air separation unit (90) is arranged to receive an air feed (4) and 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 (1 a) and the oxygen-enriched stream (91) react to provide a first synthesis gas stream (31).

Fig. 4 shows a developed layout of a hydrogen plant (500) comprising a synthesis gas stage (100) and a synthesis stage (200). The description of the synthesis gas stage (100) in the description of fig. 3 applies equally to fig. 4. Thus, the synthesis gas stage (100) is 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 disposed downstream of the reforming unit (30) and provides an internal steam feed (111) to the steam drum (120).

The steam drum (120) is arranged to dry the steam by separating 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 steam production and boiler water discharge (not shown).

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

Downstream of the superheater (220), the shifted syngas stream is then fed to a Low Temperature (LT) shift reactor (240) for further shifting. As shown, a second waste heat boiler (230) is located between the HT shift reactor and the LT shift reactor, generating a second internal steam feed (231) for the steam drum (120) by heat exchange of a boiler water stream from the steam drum (120) with a shifted syngas stream downstream of the steam superheater (220).

As shown in fig. 4, the vapor stream (123) is mixed with the oxygen-enriched stream (91). After the LT shift, the product gas is sent to a separator (250) where process condensate 252 (comprising mainly water) is removed. Thereafter, the product gas (251) is sent to a CO ₂ removal section 260, where CO ₂ is removed in the form of a CO ₂ 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.

Examples

Examples 1-4 show the results of calculations based on various parameters of the layout of fig. 4.

Example 1 no electric heater was provided at the ATR inlet. Example 2 and example 3 differ in ATR inlet temperature. It can be seen that these three embodiments achieve zero carbon emissions during the preheating process. Example 4 is the same as example 3, but the electric heater is replaced with a fired heater. This example shows that significant CO ₂ emissions were produced during the preheating process.

The invention has been described with reference to various aspects and figures. However, a person skilled in the art is able to select and combine the various aspects within the scope of the invention as 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 configured to separate the air feed (4) into at least an oxygen-rich stream (91), and supplying at least a portion of the oxygen-rich stream (91) to the ATR section (30) as the oxidant-containing feed (91), the method comprising the following steps: feeding the air feed (4) to the air separation unit (90) to provide at least an oxygen-rich stream (91), and feeding a portion of the oxygen-rich stream (91) 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 production device (500) according to claim 13, an ammonia device according to claim 14, a methanol device according to claim 15, or a synthetic fuel production device according to claim 16, the method comprising the following steps: heating a pre-reformed stream (21) in the first electric heating unit (40), and heating the pre-reformed stream (21) to a temperature of at least 400°C, preferably at least 450°C, in the first electric heating unit (40).