System for producing hydrocarbon products from synthesis gas

Abstract

A system for producing hydrocarbon products from synthesis gas, the system comprising a synthesis gas generation unit, a Fischer-Tropsch unit, a separation unit, a recycle line, a de-enrichment reactor, a carbon dioxide source, a hydrogen source, and a valve system configured to establish fluid communication in a first configuration or a second configuration.

Description

Technical Field

[0001] The present invention relates to a system for producing hydrocarbon products from synthesis gas and a method of operating such a system.

Background Art

[0002] The Fischer-Tropsch process is a series of chemical reactions that convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions are typically carried out in the presence of a metal catalyst at a temperature of 150 to 300 °C and a pressure of 1 to several tens of atmospheres. The Fischer-Tropsch process ideally involves a series of chemical reactions that produce various hydrocarbons having the formula (C n H 2n+2 ). More useful reactions produce alkanes as follows. (2n + 1)H 2 + nCO → C n H 2n+2 + nH 2 O where n is typically 1 to 100, or more. The formation of methane (n = 1) is undesirable. Most of the alkanes produced tend to be straight-chain and are suitable for the production of middle distillate fuels such as diesel fuel and jet fuel by upgrading. In addition to alkane formation, competing reactions produce small amounts of alkenes, as well as alcohols and other oxygenated hydrocarbons. By-product water is a by-product separated from the products of the Fischer-Tropsch reaction. The Fischer-Tropsch reaction is a highly exothermic reaction because it is a mixture with CO having a standard reaction enthalpy (ΔH) of -165 kJ / mol.

[0003] International Publication No. 2022 / 079408 describes a process for producing a gas stream containing carbon monoxide, comprising: (a) supplying a gas mixture containing carbon dioxide and hydrogen to a burner disposed in a reverse water gas shift vessel, and combusting the gas mixture with a sub-stoichiometric amount of oxygen gas stream to form a combustion gas mixture containing carbon monoxide, carbon dioxide, hydrogen, and water vapor; (b) passing the combustion gas mixture through a bed of a reverse water gas shift catalyst disposed in the reverse water gas shift vessel to form a crude product gas mixture containing carbon monoxide, water vapor, hydrogen, and carbon dioxide; (c) cooling the crude product gas mixture to below the dew point, recovering the condensate to form a dehydrated product gas; (d) removing carbon dioxide from the dehydrated product gas in a carbon dioxide removal unit to form a gas stream containing carbon monoxide; and (e) combining the carbon dioxide recovered by the carbon dioxide removal unit with the gas mixture containing hydrogen and carbon dioxide supplied to the reverse water gas shift vessel. The product gas stream containing carbon monoxide is supplied to a Fischer-Tropsch hydrocarbon synthesis unit. The Fischer-Tropsch exhaust gas formed by the Fischer-Tropsch hydrocarbon synthesis unit is pre-reformed in a derichment reactor to convert species containing more than one carbon atom to methane. A gas mixture containing methane and optionally non-condensable hydrocarbons recovered from the Fischer-Tropsch process is supplied to the reverse water gas shift unit. As a result, the carbon efficiency of the process is improved.

[0004] If the Fischer-Tropsch hydrocarbon synthesis unit fails, the entire plant needs to be shut down. Restarting the entire plant, including the syngas production unit, can take a long time and may lead to waste of the gas stream containing carbon monoxide. An alternative to shutting down the entire plant is to isolate the depurification reactor, depressurize it, and purge it with nitrogen. However, this causes many problems and nitrogen will be discharged, so it is costly and wasteful. In addition, the isolation valve downstream of the depurification reactor must operate at a temperature of about 550 °C, which means that it is highly likely not to function well.

[0005] The present invention aims to address at least some of the problems associated with the prior art or to provide at least a commercially acceptable alternative solution.

Summary of the Invention

[0006] One aspect of the present disclosure is a system for producing hydrocarbon products from syngas, comprising: (i) a syngas production unit, comprising: a first inlet for supplying a flow of a first feed gas containing hydrogen and carbon dioxide to the syngas production unit; one or more reaction zones downstream of the first inlet and in fluid communication with the first inlet for converting the first feed gas into carbon monoxide-enriched syngas; and a first outlet downstream of the one or more reaction zones and in fluid communication with the one or more reaction zones for passing a flow of the carbon monoxide-enriched syngas from the syngas production unit; a syngas production unit; and (ii) a Fischer-Tropsch unit comprising a reactor for converting a second feed gas containing the carbon monoxide-enriched syngas and a recycle gas mixture into a liquid product mixture containing hydrocarbon products and water, the Fischer-Tropsch reactor comprising: a second inlet for supplying a flow of the second feed gas to the Fischer-Tropsch reactor; A Fischer-Tropsch catalyst bed that is downstream of the second inlet and in fluid communication with the second inlet, for converting the second feed gas into the hydrocarbon product and the liquid product mixture containing water, the Fischer-Tropsch catalyst bed A second outlet that is downstream of the Fischer-Tropsch catalyst bed and in fluid communication with the Fischer-Tropsch catalyst bed, for passing through the liquid product mixture and a gas mixture containing gaseous by-products and unreacted synthesis gas from the Fischer-Tropsch reactor A Fischer-Tropsch unit comprising (iii) A separation unit that is downstream of the second outlet and in fluid communication with the second outlet, for separating the liquid product mixture and the gas mixture, the separation unit comprising a third outlet for the gas mixture and a fourth outlet for the liquid product mixture (iv) A recycle line for conveying a portion of the gas mixture from the third outlet as the recycle gas mixture to the second feed gas supplied to the second inlet (v) A reforming reactor for reforming a further portion of the gas mixture from the third outlet to form a lean-methane-containing exhaust gas, A third inlet for supplying the further portion of the gas mixture from the third outlet and a third feed gas containing steam to the reforming reactor A source for supplying a hydrogen stream to the reforming reactor via the third inlet or the fourth inlet A reforming catalyst bed that is downstream of the third inlet and the fourth inlet and in fluid communication with the third inlet and the fourth inlet, for converting the further portion of the gas mixture and steam into the lean-methane-containing exhaust gas, and A fifth outlet that is downstream of the reforming catalyst bed and in fluid communication with the reforming catalyst bed, for passing through the lean-methane-containing exhaust gas or a hydrogen stream from the reforming reactor, the fifth outlet being in fluid communication with the first inlet A reforming reactor comprising (vi) A carbon dioxide source in fluid communication with the first inlet; (vii) A hydrogen source in fluid communication with the first inlet; (viii) A valve system configured to establish fluid communication in a first configuration or a second configuration; comprising In the first configuration, the first outlet of the synthesis gas generation unit is in fluid communication with the second inlet of the Fischer-Tropsch reactor; the third outlet of the separation unit is in fluid communication with the third inlet of the de-enrichment reactor; the hydrogen source is not in fluid communication with either the third inlet or the fourth inlet of the de-enrichment reactor; In the second configuration, the first outlet of the synthesis gas generation unit is not in fluid communication with the second inlet of the Fischer-Tropsch reactor; the third outlet of the separation unit is not in fluid communication with the third inlet of the de-enrichment reactor; the hydrogen source is in fluid communication with either the third inlet or the fourth inlet of the de-enrichment reactor; relating to a system.

[0007] Another aspect of the present disclosure is a method of operating a system for producing hydrocarbon products from synthesis gas, the method comprising: operating the system in a first configuration; monitoring for malfunction of a Fischer-Tropsch unit; responsive to the presence of a malfunction of the Fischer-Tropsch unit, switching the system to a second configuration; relating to a method. BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0009] In a first aspect, a system for producing hydrocarbon products from synthesis gas, comprising: (i) a synthesis gas production unit having: a first inlet for supplying a first feed gas stream containing hydrogen and carbon dioxide to the synthesis gas production unit; one or more reaction zones downstream of the first inlet and in fluid communication with the first inlet for converting the first feed gas into carbon monoxide-enriched synthesis gas; and a first outlet downstream of the one or more reaction zones and in fluid communication with the one or more reaction zones for passing the carbon monoxide-enriched synthesis gas stream from the synthesis gas production unit; a synthesis gas production unit; (ii) a Fischer-Tropsch unit comprising a reactor for converting the second feed gas containing the carbon monoxide-enriched synthesis gas and the recycle gas mixture into a liquid product mixture containing the hydrocarbon products and water, wherein the Fischer-Tropsch reactor has: a second inlet for supplying the second feed gas stream to the Fischer-Tropsch reactor; a Fischer-Tropsch catalyst bed downstream of the second inlet and in fluid communication with the second inlet for converting the second feed gas into the liquid product mixture containing the hydrocarbon products and water; A second outlet downstream of the Fischer-Tropsch catalyst bed and in fluid communication with the Fischer-Tropsch catalyst bed for passing a gas mixture comprising the liquid product mixture and gaseous by-products and unreacted synthesis gas from the Fischer-Tropsch reactor. A Fischer-Tropsch unit comprising (iii) A separation unit downstream of the second outlet and in fluid communication with the second outlet for separating the liquid product mixture and the gas mixture, the separation unit comprising a third outlet for the gas mixture and a fourth outlet for the liquid product mixture. (iv) A recycle line for conveying a portion of the gas mixture from the third outlet as the recycle gas mixture to the second feed gas supplied to the second inlet. (v) A reforming reactor for reforming a further portion of the gas mixture from the third outlet to form a lean-methane-containing exhaust gas, A third inlet for supplying the further portion of the gas mixture from the third outlet and a third feed gas comprising steam to the reforming reactor, A source for supplying a hydrogen stream to the reforming reactor via the third inlet or the fourth inlet, A reforming catalyst bed downstream of the third inlet and the fourth inlet and in fluid communication with the third inlet and the fourth inlet for converting the further portion of the gas mixture and steam into lean-methane-containing exhaust gas, and A fifth outlet downstream of the reforming catalyst bed and in fluid communication with the reforming catalyst bed for passing the lean-methane-containing exhaust gas or a hydrogen stream from the reforming reactor, the fifth outlet being in fluid communication with the first inlet. A reforming reactor comprising (vi) A carbon dioxide source in fluid communication with the first inlet, (vii) A hydrogen source in fluid communication with the first inlet, (viii) a valve system configured to establish fluid communication in the first configuration or the second configuration, comprising, in the first configuration, the first outlet of the syngas generation unit is in fluid communication with the second inlet of the Fischer-Tropsch reactor, the third outlet of the separation unit is in fluid communication with the third inlet of the de-enrichment reactor, the hydrogen source is not in fluid communication with either the third inlet or the fourth inlet of the de-enrichment reactor, in the second configuration, the first outlet of the syngas generation unit is not in fluid communication with the second inlet of the Fischer-Tropsch reactor, the third outlet of the separation unit is not in fluid communication with the third inlet of the de-enrichment reactor, the hydrogen source is in fluid communication with either the third inlet or the fourth inlet of the de-enrichment reactor, relating to a system.

[0010] Each aspect or embodiment defined in this specification may be combined with any other aspect or embodiment unless explicitly indicated otherwise. Specifically, any feature shown to be preferred or advantageous may be combined with any other feature shown to be preferred or advantageous.

[0011] In a first configuration, the system can produce hydrocarbon products from synthesis gas. Advantageously, in the event of a failure of the Fischer-Tropsch unit, the separation unit, and / or the recycle line, the valve system can be operated to change the system from the first configuration to a second configuration, thereby isolating these components from the synthesis gas generation unit and the de-enrichment reactor. Thus, the synthesis gas generation unit and the de-enrichment reactor can be kept online while the failure is being repaired and the Fischer-Tropsch unit and the separation unit are being returned to an operating state. Once the failure is repaired and the Fischer-Tropsch unit and the separation unit are returned to an operating state, the system can be returned to the first configuration for producing hydrocarbon products.

[0012] By keeping the synthesis gas generation unit online during the second configuration, the startup time of the system after the failure is repaired can be reduced, typically by up to two days. Further, since the synthesis gas generation unit is kept warm, the temperature cycle of the synthesis gas generation unit is reduced, thereby extending the life of the synthesis gas generation unit. By remaining online, the synthesis gas generation unit can continue to produce synthesis gas that is ready for reintroduction to the Fischer-Tropsch unit when the entire system returns online.

[0013] By keeping the de-enrichment reactor online during the second configuration, a forward flow of gas can be maintained through the de-enrichment reactor, which can provide cooling to the equipment. As a result, it is possible to avoid the catalyst bed temperature becoming dangerously high. Further, by introducing hydrogen into the de-enrichment reactor during the second configuration, the de-enrichment catalyst can be prevented from being wetted / oxidized by the presence of water vapor. In addition, by introducing hydrogen, the formation of harmful carbonyls (e.g., nickel carbonyl) on the catalyst bed can be avoided. Such harmful carbonyls can occur when the de-enrichment reactor is isolated and not purged while the de-enrichment reactor is cooled (e.g., to less than 200°C) due to heat loss to the surroundings by the synthesis gas on the catalyst (e.g., nickel catalyst).

[0014] During the second configuration, by keeping both the syngas generation unit and the decarbonization reactor online, there is no need to purge the entire system if the Fischer-Tropsch unit, the separation unit, and / or the recycle line fails. As a result, the amount of reactants to be purged can be reduced, which means that less reactants are lost as a result of the failure.

[0015] As used herein, the term "hydrocarbon product" may include species formed from carbon and hydrogen. Hydrocarbon products typically include alkanes and typically contain from 5 to 100 or more carbon atoms per molecule.

[0016] As used herein, the term "syngas" or "synthesis gas" may include a gas mixture containing hydrogen (i.e., molecular hydrogen H 2 ) and carbon monoxide (i.e., CO). Syngas can include other species such as, for example, carbon dioxide, water, and methane.

[0017] The system includes a syngas generation unit. The syngas generation unit is known in the art.

[0018] The syngas production unit comprises one or more reaction zones downstream of and in fluid communication with the first inlet, which convert the first feed gas into carbon monoxide-enriched syngas. Each of the one or more reaction zones can convert the first feed gas into carbon monoxide-enriched syngas. Alternatively, there may be a first reaction zone that forms an intermediate gas and a second reaction zone that converts the intermediate gas into carbon monoxide-enriched syngas. This conversion includes the reverse water gas shift conversion of carbon dioxide and hydrogen into carbon monoxide and water. Preferably, at least one of the one or more reaction zones of the syngas production unit contains a reverse water gas shift catalyst. Since the reverse water gas shift reaction is endothermic, heat is provided to the one or more reaction zones. The one or more reaction zones can be heated by combustion of fuel, by heat exchange with a suitable high-temperature heat exchange medium, by electrical resistance heating, or by electrical induction heating.

[0019] In some configurations, the syngas production unit is a first reaction zone downstream of and in fluid communication with the first inlet, which is in fluid communication with an oxygen gas source and comprises a burner for partially combusting the first feed gas with the oxygen gas to form a partially combusted gas mixture, the first reaction zone, A second reaction zone that is downstream of and in fluid communication with the first reaction zone, the second reaction zone comprising a reverse water gas shift catalyst bed for converting the partially combusted gas mixture into carbon monoxide-enriched synthesis gas. In such a configuration, the first reaction zone is in fluid communication with an oxygen gas source and a burner. The reaction zone and the burner are typically housed within a container. An oxygen gas source such as an oxygen gas tank, oxygen generated by electrolysis of water, oxygen generated by an air separation unit, or oxygen generated by a pressure or vacuum swing adsorption unit is typically in fluid communication with the first reaction zone via an oxygen gas inlet. Any suitable oxygen gas source may be used. The oxygen gas purity may be at least 85 vol% or 94 vol%, preferably at least 98 vol% or 99 vol% in order to minimize inert substances such as nitrogen. The oxygen gas source is preferably provided at a pressure higher than the pressure of the first supply gas supplied to the burner, for example, up to 8 bar higher than the pressure of the first supply gas supplied to the burner, because this can create a velocity difference to promote mixing in the burner flame. The oxygen gas source may be preheated as desired to improve combustion. The burner is for partially combusting the first supply gas with oxygen gas to form a partially combusted gas mixture. Typically, the burner reacts oxygen gas with a part (but not all) of the hydrogen gas in the first supply gas to form water. In other words, the amount of oxygen gas supplied to the burner is sub-stoichiometric, i.e., insufficient to burn all the hydrogen. Thus, the molar ratio of oxygen to hydrogen (O 2 :H 2 ) is typically less than 0.5:1 and may range from 0.02 to 0.2:1 or 0.05 to 0.15:1. Thus, the partially combusted gas mixture typically contains hydrogen, carbon dioxide, and water. By burning hydrogen, heat can be generated for the subsequent reverse water gas shift reaction. Therefore, hydrogen should preferably be provided in excess of carbon dioxide so that sufficient hydrogen remains after combustion to drive the reaction forward on the reverse water gas shift catalyst.

[0020] Any burner design may be used, such as a burner used in an autothermal reformer or a secondary steam reformer. The flow may be supplied at a single point or multiple points. A burner design is preferred in which a gas mixture is supplied to the neck region of the syngas production unit and oxygen is supplied to a central conduit that passes through the neck region and opens into the combustion zone. Combustion generates a flame in the combustion zone upstream of the water gas shift catalyst. The local conditions in the combustion section, particularly in the flame front region, can be controlled by managing the momentum of the oxygen and gas flows. The water gas shift vessel may be oriented such that the combustion zone is above the bed of the reverse water gas shift catalyst. Such a configuration is used in an autothermal reformer vessel or a secondary steam reformer vessel and may be used in this process and may be referred to as autothermal reverse water-gas shift (ARWGS). However, other configurations of burners and catalysts may be used. The first feed gas is heated by combustion to a temperature typically in the range of 800 to 1300 °C.

[0021] As discussed in more detail below, prior to entering the first inlet, the first feed gas may preferably be preheated to a temperature of 400 to 1000 °C. The system may further comprise a heater for performing the preheating. Alternatively or in addition thereto, the system may comprise a heat exchanger arranged to transfer heat from the carbon monoxide enriched syngas to the first feed gas. Prior to entering the first inlet, the first feed gas may preferably be pre-pressurized to a pressure of 10 to 50 bara, more preferably to a pressure of 20 to 30 bara. The system may further comprise means for performing the pre-pressurization, such as a compressor.

[0022] The syngas generation unit comprises one or more reaction zones. At least one of the one or more reaction zones of the syngas generation unit can contain a reverse water gas shift catalyst. The reverse water gas shift catalyst is known in the art. The reverse water gas shift catalyst is suitable for converting a partial combustion gas mixture into a carbon monoxide-enriched syngas. For example, carbon dioxide and hydrogen in the partial combustion gas mixture can be converted into carbon monoxide and water on the reverse water gas shift catalyst, and any methane present in the partial combustion gas mixture can react with water to produce carbon monoxide, carbon dioxide, and hydrogen. The reaction zone containing the reverse water gas shift catalyst is typically housed in a container, and may be housed in the same container as the first reaction zone with a first inlet and a first outlet formed in the wall of the container.

[0023] This system comprises a Fischer-Tropsch unit. The Fischer-Tropsch unit is known in the art. The Fischer-Tropsch unit comprises a reactor for converting a second feed gas comprising a carbon monoxide-enriched synthesis gas and a recycle gas mixture into a liquid product mixture comprising hydrocarbon products and water. The Fischer-Tropsch catalyst bed is typically housed in a container, for example as a fixed bed. A catalyst containing cobalt is preferred, and for example, a catalyst containing 5-25 wt% cobalt on a porous alumina, titania, or silica support can be used. Since the reaction is exothermic, the catalyst is typically cooled by direct or indirect heat exchange. A fixed catalyst bed in which the catalyst is disposed in a reaction tube cooled by boiling water under pressure is preferred. In a particularly preferred arrangement, the catalyst is disposed in a plurality of catalyst carriers disposed in a reaction tube cooled by boiling water under pressure. Such carriers are described, for example, in WO 2016 / 050520 (A1). The Fischer-Tropsch unit may comprise a downstream upgrade unit in which hydrocarbon products from the Fischer-Tropsch reactor are converted into liquid hydrocarbon products such as kerosene, diesel, and naphtha, together with by-products liquid petroleum gas (LPG) and non-condensable off-gas, typically by hydrotreating using hydrogen gas.

[0024] The second inlet and the second outlet are typically formed in the wall of the container.

[0025] The system comprises a separation unit downstream of and in fluid communication with the second outlet for separating the liquid product mixture and the gas mixture. Such a separation unit is known in the art. The separation unit may comprise a conventional gas-liquid separator for separating the liquid product mixture and the gas mixture.

[0026] The system comprises a de-enrichment reactor including a de-enrichment catalyst bed. The de-enrichment reactor and the de-enrichment catalyst are known in the art. In the de-enrichment reactor, the de-enrichment catalyst bed is for converting a further portion of the gas mixture and steam into de-enriched methane-containing exhaust gas. The de-enrichment reactor houses a de-enrichment catalyst bed such as a catalyst used for adiabatic pre-reforming.

[0027] The system further comprises a carbon dioxide source in fluid communication with a first inlet.

[0028] The system further comprises a hydrogen source. There may be two hydrogen sources. The hydrogen source in fluid communication with the first inlet may be the same as or different from the hydrogen source in fluid communication with a third or fourth inlet. The hydrogen source in fluid communication with the third or fourth inlet typically contains only very low levels of carbon and more typically contains substantially no carbon. The presence of high levels of carbon in this hydrogen source may result in the formation of carbonyls in the de-enrichment reactor when the system is in the second configuration. The hydrogen source in fluid communication with the first inlet may also have a high purity, but this is not essential and, if desired, a lower purity hydrogen source may be used.

[0029] The system further comprises a valve system configured to establish fluid communication in a first configuration or a second configuration. Suitable valves are known in the art and one skilled in the art can arrange such valves to establish fluid communication in the first and second configurations. Fluid communication within the system is typically established via, for example, pipes or ducts.

[0030] The system preferably (ix) a controller for controlling the valve system.

[0031] The controller may take the form of, for example, a pre-programmed computer. The controller may enable easy switching between the first configuration and the second configuration.

[0032] The system preferably (x) A carbon monoxide-enriched synthesis gas flare unit and / or a carbon monoxide-enriched synthesis gas storage unit, wherein in a first configuration, a first outlet of the synthesis gas generation unit is not in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit, and in the second configuration, the first outlet of the synthesis gas generation unit is in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit, and further comprises a unit.

[0033] In a second configuration where the Fischer-Tropsch unit is offline, carbon monoxide-enriched synthesis gas is still generated by the synthesis gas generation unit. The carbon monoxide-enriched synthesis gas flare unit can enable the disposal of such carbon monoxide-enriched synthesis gas. The carbon monoxide-enriched synthesis gas storage unit can enable the storage of carbon monoxide-enriched synthesis gas for use when the Fischer-Tropsch unit returns online and the system is switched to the second configuration.

[0034] The system preferably (xi) means for detecting a malfunction of the Fischer-Tropsch unit, and further comprises.

[0035] Such means may comprise, for example, one or more temperature sensors. Detection of a malfunction may indicate to the operator that the system must be switched from the first configuration to the second configuration. The switching may be automated by the plant control system or may be manual.

[0036] The system is preferably configured to switch from the first configuration to the second configuration upon detection of a malfunction of the Fischer-Tropsch unit. This may enable the system to be switched more quickly upon detection of a malfunction. Therefore, any adverse effects on the de-enrichment reactor caused by a malfunction of the Fischer-Tropsch unit can be reduced.

[0037] The system is preferably configured such that when such malfunction is corrected, the second configuration switches back to the first configuration. Thereby, the time required to restart the system can be shortened.

[0038] When present in one or more reaction zones, the reverse water gas shift catalyst may be any suitable transition metal oxide catalyst. The reverse water gas shift catalyst preferably contains nickel, and more preferably the reverse water gas shift catalyst contains 3 to 20% by weight of nickel represented as NiO on a refractory metal oxide support based on the total weight of the reverse water gas shift catalyst. Such a catalyst may be particularly suitable for performing the reverse water gas shift reaction at advantageous temperatures and pressures and with a high conversion rate. In addition, such a catalyst may be capable of steam reforming any hydrocarbons contained in the first feed gas.

[0039] The reverse water gas shift catalyst may be on a suitable refractory metal oxide support. The refractory metal oxide support may include zirconia, alumina, calcium aluminate, magnesium aluminate, titania magnesia, or a mixture thereof. More preferably, the catalyst includes nickel oxide on zirconia, nickel oxide on α-alumina, nickel oxide on calcium aluminate, or nickel oxide on magnesium aluminate.

[0040] The water-gas shift catalyst may be particulate, for example in the form of shaped units such as pellets, rings or extrudates, which may be leaf-shaped or grooved. The catalytically active metal, such as nickel, may be dispersed throughout the particulate catalyst or may be present only within an eggshell layer having a thickness of 200 to 1000 micrometers on the surface of the refractory support. Alternatively, the catalyst may comprise one or more monolith supports such as metal or ceramic foams or honeycombs that carry the catalytically active metal. Preferably, the catalyst is a particulate catalyst, more preferably a four-hole cylinder, and in particular leaf-shaped or grooved in order to provide a higher geometric surface area (GSA) than a solid cylinder of the same size without increasing the pressure drop. A catalyst having a GSA in the range of 400 to 550 m 2 per cubic meter is preferred.

[0041] Optionally, a layer of zirconia balls, pellets or tiles may be disposed over the catalyst to protect the surface of the catalyst from the irregularities of the combustion gas flow. The advantage of providing this layer is to prevent turbulence on the surface of the catalyst bed.

[0042] The outlet temperature may be in the range of 700 °C to 1050 °C, preferably 750 to 950 °C.

[0043] The Fischer-Tropsch catalyst preferably comprises cobalt, iron, and / or ruthenium, more preferably cobalt. Such catalysts are particularly effective in catalyzing the Fischer-Tropsch reaction and / or can advantageously cause the reaction to proceed at low temperature and / or in high yield.

[0044] The Fischer-Tropsch catalyst may be particulate, for example in the form of shaped units such as pellets, rings, or extrudates, which may be leaf-shaped or grooved.

[0045] The defluorination catalyst preferably contains nickel, more preferably with a nickel content represented as NiO in the range of 30 to 90% by weight. Such a catalyst can be particularly suitable for performing the defluorination reaction at advantageous temperatures and pressures and with a high conversion rate.

[0046] The defluorination catalyst may be in the form of particles, for example, in the form of shaped units such as pellets, rings, or extrudates, which may be leaf-shaped or grooved.

[0047] When an oxygen source is used, the system may further comprise an electrolysis unit and / or an air separation unit for providing the oxygen source. Preferably, the electricity for the electrolysis unit is generated using renewable energy.

[0048] Preferably, the system further comprises an electrolysis unit for providing a hydrogen source, a high-purity hydrogen separation unit, and / or a hydrogen storage unit.

[0049] Preferably, the system further comprises a hydrocarbon-water separator downstream of and in fluid communication with the fourth outlet of the separation unit for separating the liquid product mixture into a hydrocarbon product stream and a water stream. The water stream can be converted to steam and introduced into the third inlet of the defluorination reactor.

[0050] In a further aspect, the present disclosure is a method of operating the system described herein for producing hydrocarbon products from synthesis gas, comprising: operating the system in a first configuration; monitoring for malfunction of the Fischer-Tropsch unit; in response to the presence of a malfunction of the Fischer-Tropsch unit, switching the system to a second configuration; and relates to a method.

[0051] To avoid misunderstanding, the advantages and preferred features of the first aspect equally apply to this aspect as well.

[0052] The method preferably continues to monitor for malfunction of the Fischer-Tropsch unit after switching the system to the second configuration, and in response to there being no malfunction of the Fischer-Tropsch unit, returns the system to the first configuration, and further includes.

[0053] The first feed gas preferably has a hydrogen to carbon dioxide molar ratio of 2:1 to 10:1. As discussed above, hydrogen should be provided in excess of carbon dioxide so that sufficient hydrogen remains after combustion to drive the reaction forward on the reverse water gas shift catalyst. The excess hydrogen is also desirable in view of the potential end use of the carbon monoxide-containing gas in the Fischer-Tropsch synthesis of hydrocarbons where the H 2 :CO ratio is preferably about 2:1. The molar ratio of hydrogen to carbon dioxide in the first feed gas may range from 1:1 to 5:1. This ratio can vary depending on the conversion of carbon dioxide achieved on the reverse water gas shift bed and the hydrogen to carbon monoxide ratio desired in the downstream process.

[0054] The first feed gas preferably contains 15 to 50% by volume of carbon dioxide, preferably 25 to 40% by volume of carbon dioxide. The first feed gas supplied to the syngas production unit preferably contains less than 10% by volume in total of other gases such as steam, nitrogen, carbon monoxide, and methane.

[0055] Any suitable carbon dioxide source may be used. The carbon dioxide source is preferably obtained from syngas produced by partial oxidation or steam reforming of hydrocarbons or by vaporization of a carbonaceous feed, or from the flue gas of a furnace or boiler heated by combustion of a fossil fuel or carbonaceous waste, or from air or seawater.

[0056] The first feed gas is preferably preheated to a temperature of 400 to 1000 °C, more preferably 450 to 800 °C, and even more preferably 500 to 600 °C before passing through the first inlet of the synthesis gas generation unit. Such preheating can assist combustion.

[0057] The oxygen source, if required, preferably provides oxygen at a molar ratio of oxygen to hydrogen in the first feed gas of less than 0.5:1, preferably 0.02 to 0.2:1, more preferably 0.05 to 0.15:1 (O 2 :H 2 ). Such a ratio can ensure partial combustion of the hydrogen gas in the first feed gas.

[0058] The carbon monoxide-enriched synthesis gas preferably has a hydrogen-to-carbon monoxide molar ratio of 1.0 to 2.5:1, preferably 1.2 to 2.5:1, more preferably 1.6 to 2.2:1, and even more preferably 2.0 to 2.1:1. Such a ratio is close to the stoichiometric ratio of the Fischer-Tropsch reaction.

[0059] In the first configuration, the temperature of the Fischer-Tropsch catalyst bed is preferably 150 °C to 300 °C. Such a temperature can enable the Fischer-Tropsch reaction to be carried out with high efficiency and high yield.

[0060] The temperature of the third feed gas supplied to the de-enrichment reactor is preferably 250 to 650 °C, preferably 300 to 550 °C.

[0061] The third feed gas preferably has a steam-to-carbon molar ratio of 0.2:1 to 5:1, preferably 0.3:1 to 3:1.

[0062] The de-enrichment reactor preferably operates at a pressure of 10 to 50 bara.

[0063] In the second configuration, the gas contacting the de-enrichment catalyst preferably has a maximum steam-to-hydrogen (H 2)It has a ratio. Thereby, damage to the de-enrichment catalyst can be avoided.

[0064] The present invention includes using the system and method described above for the de-enrichment reactor for one or more additional parallel de-enrichment reactors to which one or more further recycle streams suitable for conversion in one or more additional parallel de-enrichment reactors in the methane-containing gas stream supplied to the synthesis gas generation unit can be supplied. For example, a parallel de-enrichment reactor can be used to convert a hydrocarbon recycle stream from a second separation unit within a Fischer-Tropsch unit to form a de-enriched methane-containing recycle stream that can likewise be supplied to the synthesis gas generation unit. Thus, as described above, a further valve system is provided to enable the system to operate in a third configuration or a fourth configuration for each of the one or more further parallel de-enrichment reactors. Thus, the system and method may comprise a second separation unit, a further parallel de-enrichment reactor, and a further valve system configured to establish fluid communication in a third configuration or a fourth configuration, The method includes operating the system in the third configuration, monitoring for malfunction of the Fischer-Tropsch unit, responding to the presence of a malfunction of the Fischer-Tropsch unit by switching the system to the fourth configuration, and further includes, In the third configuration, a first outlet of the synthesis gas generation unit is in fluid communication with a second inlet of the Fischer-Tropsch reactor, an outlet of the second separation unit is in fluid communication with an inlet of the further parallel de-enrichment reactor, a hydrogen source is optionally not in fluid communication with the inlet of the further parallel de-enrichment reactor, In the fourth configuration, the first outlet of the synthesis gas generation unit is not in fluid communication with the second inlet of the Fischer-Tropsch reactor, The outlet of the second separation unit is not in fluid communication with the inlet of the further parallel de-ethanization reactor, and a hydrogen source is in fluid communication with the inlet of the further parallel de-ethanization reactor.

[0065] The present invention will now be described in connection with the following non-limiting examples.

[0066] Example An example of a system according to the present invention will be described with reference to FIGS. 1 to 5.

[0067] As shown in FIGS. 1 to 5, an exemplary system (designated as A as a whole) is for producing hydrocarbon products from synthesis gas. The system includes a first inlet 3a for supplying a flow of a first feed gas containing hydrogen and carbon dioxide to a synthesis gas production unit 3, and a first reaction zone 3b downstream of and in fluid communication with the first inlet 3a, the first reaction zone 3b being in fluid communication with an oxygen gas source 4 and including a burner 3c for partially combusting the first feed gas with oxygen gas to form a partially combusted gas mixture, a second reaction zone 3d downstream of and in fluid communication with the first reaction zone 3b, the second reaction zone 3d including a reverse water gas shift catalyst bed 3e for converting the partially combusted gas mixture into carbon monoxide-enriched synthesis gas, and a first outlet 3f downstream of and in fluid communication with the second reaction zone 3d for passing a flow of carbon monoxide-enriched synthesis gas from the synthesis gas production unit 3.

[0068] This system further comprises a Fischer-Tropsch unit 5 comprising a reactor 5a for converting a second feed gas comprising a carbon monoxide-enriched synthesis gas and a recycle gas mixture into a liquid product mixture comprising hydrocarbon products and water. The Fischer-Tropsch reactor 5 comprises a second inlet 5b for supplying a flow of the second feed gas to the Fischer-Tropsch reactor, and a Fischer-Tropsch catalyst bed 5c downstream of and in fluid communication with the second inlet 5b, the Fischer-Tropsch catalyst bed 5c for converting the second feed gas into a liquid product mixture comprising hydrocarbon products and water, and a second outlet 5d downstream of and in fluid communication with the Fischer-Tropsch catalyst bed 5c for passing the liquid product mixture and a gas mixture comprising gaseous by-products and unreacted synthesis gas through the Fischer-Tropsch reactor (5).

[0069] The system further comprises a separation unit 6 downstream of and in fluid communication with the second outlet 5d for separating the liquid product mixture and the gas mixture, the separation unit 6 comprising a third outlet 6a for the gas mixture and a fourth outlet 6b for the liquid product mixture.

[0070] The system further comprises a recycle line 7 for conveying a portion of the gas mixture from the third outlet 6a as a recycle gas mixture to the second feed gas supplied to the second inlet 5b.

[0071] The system further comprises a reforming reactor 8 for converting a further portion of the gas mixture from the third outlet 6a into reformed methane-containing exhaust gas, the reforming reactor 8 having a third inlet 8a for supplying a third feed gas containing the further portion of the gas mixture from the third outlet 6a and steam 9 to the reforming reactor 8, a fourth inlet 8b for supplying a hydrogen stream to the reforming reactor, a reforming catalyst bed 8c downstream of and in fluid communication with the third inlet 8a and the fourth inlet 8b, the reforming catalyst bed 8c for converting the further portion of the gas mixture and steam into reformed methane-containing exhaust gas, and a fifth outlet (8d) downstream of and in fluid communication with the reforming catalyst bed 8c, the fifth outlet (8d) being in fluid communication with the first inlet 3a for passing reformed methane-containing exhaust gas or a hydrogen stream out of the reforming reactor.

[0072] The system further comprises a carbon dioxide source 2 in fluid communication with the first inlet 3a, a hydrogen source 1 in fluid communication with the first inlet 3a, and a valve system (see FIGS. 4 and 5) configured to establish fluid communication in a first configuration or a second configuration.

[0073] The system further comprises a carbon monoxide-enriched synthesis gas flare unit and / or a carbon monoxide-enriched synthesis gas storage unit 10.

[0074] The small loop purge 11 is provided to prevent the undesired accumulation of inert gases such as nitrogen in the Fischer-Tropsch reaction loop.

[0075] Figures 2 and 3 show the systems in the first and second configurations respectively, and the dashed lines indicate unused lines. As can be seen from Figure 2, in the first configuration, the first outlet 3f of the synthesis gas generation unit 3 is in fluid communication with the second inlet 5b of the Fischer-Tropsch reactor 5, the third outlet 6a of the separation unit 6 is in fluid communication with the third inlet 8a of the de-enrichment reactor 8, the hydrogen source 1 is not in fluid communication with the fourth inlet 8b of the de-enrichment reactor 8, and the first outlet 3f of the synthesis gas generation unit 3 is not in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit 10.

[0076] As can be seen from Figure 3, in the second configuration, the first outlet 3f of the synthesis gas generation unit 3 is not in fluid communication with the second inlet 5b of the Fischer-Tropsch reactor 5, the third outlet 6a of the separation unit 6 is not in fluid communication with the third inlet 8a of the de-enrichment reactor 8, the hydrogen source 1 is in fluid communication with the fourth inlet 8b of the de-enrichment reactor 8, and the first outlet 3f of the synthesis gas generation unit 3 is in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit 10.

[0077] Figures 4 and 5 show the systems in the first and second configurations respectively, and show the valve system. The valves without shading are open, and the shaded valves are closed.

[0078] The foregoing detailed description is provided for purposes of illustration and example and is not intended to limit the scope of the appended claims. Many variations of the presently preferred embodiments shown herein will be apparent to those skilled in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. A system for producing hydrocarbon products from synthesis gas, comprising: (i) a synthesis gas generation unit, comprising: a first inlet for supplying a flow of a first feed gas containing hydrogen and carbon dioxide to the synthesis gas generation unit; one or more reaction zones downstream of and in fluid communication with the first inlet for converting the first feed gas into carbon monoxide-enriched synthesis gas; and a first outlet downstream of and in fluid communication with the one or more reaction zones for passing a flow of the carbon monoxide-enriched synthesis gas from the synthesis gas generation unit; a synthesis gas generation unit; (ii) a Fischer-Tropsch unit comprising a reactor for converting the second feed gas containing the carbon monoxide-enriched synthesis gas and the recycle gas mixture into a liquid product mixture containing the hydrocarbon products and water, the Fischer-Tropsch reactor comprising: a second inlet for supplying a flow of the second feed gas to the Fischer-Tropsch reactor; a Fischer-Tropsch catalyst bed downstream of and in fluid communication with the second inlet for converting the second feed gas into the liquid product mixture containing the hydrocarbon products and water; a second outlet downstream of and in fluid communication with the Fischer-Tropsch catalyst bed for passing the liquid product mixture and a gas mixture containing gaseous by-products and unreacted synthesis gas from the Fischer-Tropsch reactor; a Fischer-Tropsch unit; (iii) a separation unit downstream of and in fluid communication with the second outlet for separating the liquid product mixture from the gas mixture, the separation unit comprising a third outlet for the gas mixture and a fourth outlet for the liquid product mixture; (iv) a recycle line for conveying a portion of the gas mixture from the third outlet as the recycle gas mixture to the second feed gas supplied to the second inlet; (v) a de-enrichment reactor for converting a further portion of the gas mixture from the third outlet to form a de-enriched methane-containing exhaust gas; A third inlet for supplying a further portion of the gas mixture from the third outlet and a third feed gas containing steam to the de-enrichment reactor, A source for supplying a hydrogen stream to the de-enrichment reactor via the third inlet or the fourth inlet, A de-enrichment catalyst bed downstream of the third inlet and the fourth inlet and in fluid communication with the third inlet and the fourth inlet, for converting the further portion of the gas mixture and steam into a de-enriched methane-containing exhaust gas, a de-enrichment catalyst bed, and A fifth outlet downstream of the de-enrichment catalyst bed and in fluid communication with the de-enrichment catalyst bed, for passing the de-enriched methane-containing exhaust gas or the hydrogen stream from the de-enrichment reactor, and being in fluid communication with the first inlet, a fifth outlet , comprising a de-enrichment reactor; (vi) A carbon dioxide source in fluid communication with the first inlet; (vii) A hydrogen source in fluid communication with the first inlet; (viii) A valve system configured to establish fluid communication in a first configuration or a second configuration; comprising; In the first configuration, The first outlet of the synthesis gas generation unit is in fluid communication with the second inlet of the Fischer-Tropsch reactor; The third outlet of the separation unit is in fluid communication with the third inlet of the de-enrichment reactor; The hydrogen source is not in fluid communication with either the third inlet or the fourth inlet of the de-enrichment reactor; In the second configuration, The first outlet of the synthesis gas generation unit is not in fluid communication with the second inlet of the Fischer-Tropsch reactor; The third outlet of the separation unit is not in fluid communication with the third inlet of the de-enrichment reactor; The hydrogen source is in fluid communication with the third inlet or the fourth inlet of the de-enrichment reactor; A system.

2. (ix) A controller for controlling the valve system, further comprising the system according to claim 1.

3. (x) A carbon monoxide-enriched synthesis gas flare unit and / or a carbon monoxide-enriched synthesis gas storage unit, further comprising, In the first configuration, the first outlet of the synthesis gas generation unit is not in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit, In the second configuration, the first outlet of the synthesis gas generation unit is in fluid communication with the carbon monoxide-enriched synthesis gas flare unit and / or the carbon monoxide-enriched synthesis gas storage unit, according to the system of claim 1 or claim 2.

4. (xi)Means for detecting a malfunction of the Fischer-Tropsch unit, further comprising the system according to any one of claims 1 to 3.

5. The system is configured to switch from the first configuration to the second configuration when a malfunction of the Fischer-Tropsch unit is detected, according to the system of claim 4.

6. The system is configured such that when such a malfunction is corrected, the second configuration switches back to the first configuration, according to the system of claim 5.

7. At least one of the one or more reaction zones of the synthesis gas generation unit includes a reverse water gas shift catalyst, according to the system of any one of claims 1 to 6.

8. The synthesis gas generation unit is a first reaction zone downstream of the first inlet and in fluid communication with the first inlet, in fluid communication with an oxygen gas source, and comprising a burner for partially burning the first feed gas with oxygen gas to form a partially burned gas mixture, a first reaction zone, A second reaction zone downstream of the first reaction zone and in fluid communication with the first reaction zone, comprising a reverse water gas shift catalyst bed for converting the partially burned gas mixture into carbon monoxide-enriched synthesis gas, a second reaction zone, according to the system of any one of claims 1 to 7.

9. The reverse water gas shift catalyst contains nickel, according to the system of claim 7 or claim 8.

10. The reverse water gas shift catalyst contains 3 to 20% by weight of nickel represented as NiO on a refractory metal oxide support, based on the total weight of the reverse water gas shift catalyst, according to the system of claim 9.

11. The Fischer-Tropsch catalyst contains cobalt, iron, and / or ruthenium, preferably cobalt, according to the system of any one of claims 1 to 10.

12. The de-enrichment catalyst contains nickel, and preferably, the nickel content represented as NiO is in the range of 30 to 90% by weight, according to the system of any one of claims 1 to 11.

13. The system according to any one of claims 8 to 12, further comprising an electrolysis unit and / or an air separation unit for providing the oxygen source.

14. The system according to any one of claims 1 to 13, further comprising an electrolysis unit, a high-purity hydrogen separation unit, and / or a hydrogen storage unit for providing the hydrogen source, which is in fluid communication with the third inlet or the fourth inlet and optionally in fluid communication with the first inlet.

15. A method of operating the system according to any one of claims 1 to 14 to produce hydrocarbon products from syngas, comprising: operating the system in a first configuration; monitoring for malfunctions of the Fischer-Tropsch unit; responding to the presence of a malfunction of the Fischer-Tropsch unit by switching the system to a second configuration. A method comprising the above steps.

16. The method further comprises: continuing to monitor for malfunctions of the Fischer-Tropsch unit after switching the system to the second configuration; responding to the absence of a malfunction of the Fischer-Tropsch unit by returning the system to the first configuration. The method according to claim 15, further comprising the above steps.

17. The method according to claim 15 or claim 16, wherein the first feed gas has a hydrogen to carbon dioxide molar ratio of 2:1 to 10:

1.

18. The method according to any one of claims 15 to 17, wherein the first feed gas contains 15 to 50% by volume of carbon dioxide, preferably 25 to 40% by volume of carbon dioxide.

19. The method according to any one of claims 15 to 18, wherein the carbon dioxide source is obtained from syngas produced by partial oxidation or steam reforming of hydrocarbons or by gasification of a carbonaceous feed, or from the flue gas of a furnace or boiler heated by combustion of a fossil fuel or carbonaceous waste, or from air or seawater.

20. The method according to any one of claims 15 to 19, wherein the carbon monoxide-enriched syngas has a hydrogen to carbon monoxide molar ratio of 1.0 to 2.5:1, preferably 1.2 to 2.5:1, more preferably 1.6 to 2.2:1, and even more preferably 2.0 to 2.1:

1.

21. The method according to any one of claims 15 to 20, wherein in the first configuration, the temperature of the Fischer-Tropsch catalyst bed is 150°C to 300°C.

22. The method according to any one of claims 15 to 21, wherein the temperature of the third feed gas supplied to the de-enrichment reactor is 250 to 650 °C, preferably 300 to 550 °C.

23. The method according to any one of claims 15 to 22, wherein the third feed gas has a steam-to-carbon molar ratio of 0.2:1 to 5:1, preferably 0.3:1 to 3:

1.

24. The method according to any one of claims 15 to 23, wherein the de-enrichment reactor operates at a pressure of 10 to 50 bara.

25. In the second configuration, the gas contacting the de-enrichment catalyst has a maximum steam-to-hydrogen (H ２ ) ratio of 10 to 1, the method according to any one of claims 15 to 24.

26. The system comprises a second separation unit, a further parallel de-enrichment reactor, and a further valve system configured to establish fluid communication in a third configuration or a fourth configuration, The method further comprises operating the system in the third configuration, monitoring for malfunctions of the Fischer-Tropsch unit, responding to the presence of a malfunction of the Fischer-Tropsch unit by switching the system to the fourth configuration, and further comprising In the third configuration, the first outlet of the synthesis gas generation unit is in fluid communication with the second inlet of the Fischer-Tropsch reactor, the outlet of the second separation unit is in fluid communication with the inlet of the further parallel de-enrichment reactor, the hydrogen source is optionally not in fluid communication with the inlet of the further parallel de-enrichment reactor, In the fourth configuration, the first outlet of the synthesis gas generation unit is not in fluid communication with the second inlet of the Fischer-Tropsch reactor, the outlet of the second separation unit is not in fluid communication with the inlet of the further parallel de-enrichment reactor, the hydrogen source is in fluid communication with the inlet of the further parallel de-enrichment reactor, The method according to any one of claims 15 to 25.

Images