Method for forming liquid hydrocarbon products

Abstract

A method for forming a liquid hydrocarbon product, comprising: providing a feed gas containing compounds of carbon, hydrogen, and oxygen elements; generating a synthesis gas from the feed gas, wherein the synthesis gas contains carbon monoxide, hydrogen, and vapor; cooling the synthesis gas to below its dew point to form an aqueous condensate and a water-removed synthesis gas, wherein the aqueous condensate has a carbon-containing gas dissolved therein; passing the aqueous condensate through a first stripper; stripping the aqueous condensate with vapor to transfer the carbon-containing gas from the aqueous condensate to vapor; thereby, the stripped aqueous condensate and the first The process includes forming stripper exhaust steam, passing the water-removed synthesis gas through a Fischer-Tropsch unit to form liquid hydrocarbon products and production-associated water, wherein the production-associated water contains dissolved carbon-containing substances, passing the production-associated water through a second stripper, stripping the production-associated water with first stripper exhaust steam to transfer carbon-containing substances from the production-associated water to the first stripper exhaust steam, thereby forming stripped production-associated water and second stripper exhaust steam, and reusing the second stripper exhaust steam as a feed gas.

Description

Technical Field

[0001] The present invention relates to a method for forming liquid hydrocarbon products.

Background Art

[0002] The Fischer-Tropsch process utilizes chemical reactions to convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions occur typically at temperatures of 150 to 300 °C and pressures of 1 to several tens of atmospheres in the presence of a metal catalyst. The Fischer-Tropsch process ideally produces various hydrocarbons having the formula (C n H 2n+2 ). More useful reactions produce alkanes as follows: (2n + 1)H2 + nCO → C n H 2n+2 + nH2O where n is typically 1 to 100. The formation of methane (n = 1) is undesirable. In addition to alkane formation, competing reactions result in small amounts of alkenes, as well as alcohols and other oxygenated hydrocarbons. The Fischer-Tropsch reaction is a highly exothermic reaction because the standard reaction enthalpy (ΔH) is -165 kJ / mol CO in total.

[0003] The syngas feed to a Fischer-Tropsch unit can be derived from many feedstocks, such as natural gas by steam reforming and / or autothermal reforming, municipal solid waste and biomass by high-temperature gasification, or carbon dioxide and hydrogen by the reverse water-gas shift reaction. The latter source is beneficial because it utilizes carbon dioxide that may otherwise be released into the atmosphere.

[0004] International Publication No. 2022 / 079408(A1) discloses the use of an autothermally reversed water-gas shift unit in a hydrocarbon synthesis process. Process condensate is recovered from the reversed water-gas shift unit, and production-associated water is recovered from a hydrocarbon synthesis (Fischer-Tropsch) unit. The process condensate and production-associated water are separately stripped to reduce their organic pollutants, reduce the burden on downstream water treatment, and return carbon to the process. Such a process requires a large amount of steam. As a result, the energy and water requirements of the process are high. Furthermore, the water content of the stripping effluent from at least the stripped process condensate is high, meaning that not all of the stripping effluent can be recycled back into the process. This results in a penalty to the carbon efficiency of the process. Different examples of stripped condensate or Fischer-Tropsch water are disclosed in International Publication Nos. 2021175785(A1) and International Publication No. 2021185865(A1), respectively.

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

[0006] This disclosure relates to a method for forming a liquid hydrocarbon product, To provide a supply gas containing compounds of carbon, hydrogen, and oxygen elements, The process involves generating synthesis gas from a supply gas, wherein the synthesis gas contains carbon monoxide, hydrogen, and vapor. The synthesis gas is cooled to below its dew point to form an aqueous condensate and a water-removed synthesis gas, wherein the aqueous condensate contains dissolved carbon-containing gas. The aqueous condensate is passed through a first stripper, and the aqueous condensate is stripped with steam to transfer carbon-containing gas from the aqueous condensate to the steam, thereby forming the stripped aqueous condensate and the steam discharged from the first stripper. The process involves passing a water-removed synthesis gas through a Fischer-Tropsch unit to form a liquid hydrocarbon product and associated water, wherein the associated water contains dissolved carbon-containing substances. The production-associated water is passed through a second stripper, and the production-associated water is stripped with the first stripper discharge steam to form the stripped production-associated water and the second stripper discharge steam. The present invention relates to a method comprising recirculating a second stripper exhaust vapor into the supply gas. [Brief explanation of the drawing]

[0007] [Figure 1] A flowchart of one embodiment of the method according to the present invention is shown. [Figure 2] A flowchart of a further embodiment of the method according to the present invention is shown. [Modes for carrying out the invention]

[0008] In a first embodiment, the present disclosure relates to a method for forming a liquid hydrocarbon product, To provide a supply gas containing compounds of carbon, hydrogen, and oxygen elements, The process involves generating synthesis gas from a supply gas, wherein the synthesis gas contains carbon monoxide, hydrogen, and vapor. The synthesis gas is cooled to below its dew point to form an aqueous condensate and a water-removed synthesis gas, wherein the aqueous condensate contains dissolved carbon-containing gas. The aqueous condensate is passed through a first stripper, and the aqueous condensate is stripped with steam to transfer carbon-containing gas from the aqueous condensate to the steam, thereby forming the stripped aqueous condensate and the steam discharged from the first stripper. The process involves passing a water-removed synthesis gas through a Fischer-Tropsch unit to form a liquid hydrocarbon product and associated water, wherein the associated water contains dissolved carbon-containing substances. The production-associated water is passed through a second stripper, and the production-associated water is stripped with the exhaust steam from the first stripper to transfer carbon-containing substances from the production-associated water to the exhaust steam from the first stripper, thereby forming the stripped production-associated water and the exhaust steam from the second stripper. The present invention relates to a method comprising recirculating a second stripper exhaust vapor into the supply gas.

[0009] Each aspect or embodiment defined herein may be combined with any other aspect or embodiment unless expressly indicated otherwise. Specifically, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0010] Advantageously, recirculating the second stripper exhaust steam into the feed gas may increase the carbon efficiency of the process. In contrast to aqueous condensate and production-associated water, the second stripper exhaust steam is a gas, typically in the form of a high-pressure gas, which means it can be reintroduced into the feed gas without requiring any significant preheating and / or pressurization steps. As a result, the energy efficiency of the process may increase.

[0011] Because aqueous condensate is derived from the synthesis gas production process, it tends to be relatively "clean" or purer compared to the production-generated water formed in the Fischer-Tropsch unit. In other words, it tends to contain lower levels of carbon-containing gases and / or carbon-containing substances. This means that the first stripper exhaust steam may be suitable for use when stripping "dirtier" or more heavily contaminated production-generated water. By using the first stripper exhaust steam to strip the production-generated water, this method requires less steam compared to conventional methods in which the aqueous condensate and production-generated water are stripped in separate stripper units, i.e., in parallel. Therefore, the water and energy requirements of this method can be reduced compared to conventional methods. Furthermore, in conventional methods using "parallel" stripping, the aqueous stripper exhaust steam may have relatively low concentrations of organic matter and relatively high concentrations of steam. This may mean that aqueous stripper exhaust vapors are unsuitable for recirculation into the feed gas without further energy-intensive treatment processes and must instead be discarded, thereby incurring waste disposal costs and resulting in the loss of organic or carbon compounds from the process. In other words, the method of the present invention can enable the recirculation of substantially all organic matter contained in both stripper exhaust vapors.

[0012] Compared to alternative methods in which aqueous condensate and production-associated water are combined and then stripped in a single stripper unit, the method of the present invention can yield a final stripper exhaust steam (i.e., a second stripper exhaust steam) with a higher concentration of organic matter. This can be more suitable for recirculation as feed gas for use in the synthesis gas production process. Furthermore, the method of the present invention can yield two stripped products: stripped aqueous condensate and stripped production-associated water. This is beneficial because the stripped aqueous condensate obtained from the synthesis gas production process is likely to be "cleaner" (lower Chemical Oxygen Demand, COD) than the stripped production-associated water obtained from the Fischer-Tropsch reaction. This means that the stripped aqueous condensate can be processed more easily. As a result, the overall water treatment burden of the method may be reduced.

[0013] This method forms a liquid hydrocarbon product. As used herein, the term “liquid hydrocarbon” may encompass species formed from carbon and hydrogen that are liquid at room temperature and room pressure. Hydrocarbons typically include alkanes and typically contain 5 to 30 carbon atoms per molecule. This method preferably includes recovering the liquid hydrocarbon product.

[0014] This method involves providing a feed gas containing compounds of carbon, hydrogen, and oxygen. To avoid misunderstanding, the feed gas contains each of carbon, hydrogen, and oxygen. However, the compounds contained in the feed gas may contain only one, two, or all three of these elements. For example, the feed gas may contain carbon dioxide (CO2) and hydrogen (H2), and / or methane (CH4) and water vapor (H2O).

[0015] This method includes generating synthesis gas from a feed gas, and the synthesis gas includes carbon monoxide (CO), hydrogen (H2), and steam (H2O). As will be described in more detail below, the generation of synthesis gas may include, for example, a reverse water-gas shift reaction and / or a steam reforming reaction and / or a partial oxidation reaction.

[0016] As used herein, the term "reverse-water-gas-shift reaction" refers to a reaction that reacts carbon dioxide and hydrogen to form carbon monoxide and steam, that is,

[0017]

Chemical formula

[0018] As used herein, the term "steam reforming reaction" refers to a reaction of methane and steam to form carbon monoxide and hydrogen, that is,

[0019]

Chemical formula

[0020] As used herein, the term "partial oxidation" refers to a reaction of methane and molecular oxygen to form carbon monoxide and hydrogen, that is,

[0021]

Chemical formula

[0022] The method of the present invention involves cooling a synthesis gas to below its dew point to form an aqueous condensate and a water-removed synthesis gas. As used herein, the term “dew point” may encompass the temperature at which the gas must be cooled to saturate with water vapor, assuming constant pressure and temperature. Cooling below the dew point forms an aqueous condensate. The aqueous condensate contains a dissolved carbon-containing gas (i.e., a gas of one or more carbon-containing compounds). Such a carbon-containing gas may include, for example, one or more of carbon monoxide, carbon dioxide, and methane.

[0023] This method involves passing an aqueous condensate through a first stripper and stripping the aqueous condensate with steam. As used herein, the term “stripping” may encompass a physical separation process in which one or more components are removed from a liquid flow by a steam flow. Suitable stripping apparatuses are known in the art. Stripping is typically carried out in a packed column or tray column, but may also be carried out in, for example, a spray column, a bubble column, and / or a centrifugal contactor. Stripping is typically carried out at high temperature and / or high pressure. Suitable high temperature and high pressure are known in the art. Stripping can transfer a carbon-containing gas from the aqueous condensate to steam, thereby forming the stripped aqueous condensate and the first stripper exhaust steam. Stripping typically transfers most of the carbon-containing gas from the aqueous condensate, more typically at least 50% by mass, more typically at least 75% by mass, even more typically at least 90% by mass, even more typically at least 95% by mass, and even more typically substantially all of the carbon-containing gas, into vapor.

[0024] The method further includes passing the water-removed synthesis gas through a Fischer-Tropsch unit to form a liquid hydrocarbon product and associated water. Fischer-Tropsch units are known in the art. The Fischer-Tropsch process uses a series of chemical reactions to convert a mixture of carbon monoxide and hydrogen into a liquid hydrocarbon. These reactions typically occur at temperatures of 150–300°C and pressures of 1–tens of atmospheres in the presence of a metal catalyst. The Fischer-Tropsch process is ideally based on formula (C n H 2n+2 This reaction produces various hydrocarbons containing ) . More useful reactions produce alkanes as follows: (2n+1)H2+nCO→C n H 2n+2 +nH2O In the formula, n is typically between 1 and 100.

[0025] The produced water formed as a result of the Fischer-Tropsch reaction contains dissolved carbon-containing substances (carbon-containing compounds). Such carbon-containing substances may include, for example, one or more of the following: carbon monoxide, carbon dioxide, methane, alcohols, and carboxylic acids.

[0026] The method further includes passing the production-produced water through a second stripper and stripping the production-produced water with the exhaust steam from the first stripper to transfer carbon-containing material from the production-produced water to the exhaust steam from the first stripper, thereby forming stripped production-produced water and the exhaust steam from the second stripper. As described above, suitable stripper apparatuses are known in the art. The first and second strippers may be the same or different. The stripping process is typically carried out at high temperature and / or high pressure. The stripping process typically transfers most of the carbon-containing material, more typically at least 50% by mass, more typically at least 75% by mass, even more typically at least 90% by mass, even more typically at least 95% by mass, and even more typically substantially all of the carbon-containing material from the aqueous condensate to the steam.

[0027] The method further includes recirculating the second stripper exhaust vapor into the feed gas. As described above, being a high-pressure gas, the second stripper exhaust vapor may be incorporated into the feed gas without any substantial pressurization and / or heating steps. Carbon-containing substances in the second stripper exhaust vapor, such as one or more of carbon monoxide, carbon dioxide, methane, alcohols, and carboxylic acids, may be converted into synthesis gas.

[0028] Producing synthesis gas from a feed gas preferably involves converting at least a portion of the feed gas to carbon monoxide. Usefully, the reaction for converting the feed gas to carbon monoxide uses water vapor. The use of water vapor in these reactions is advantageous because it reduces catalyst deactivation.

[0029] Preferably, the feed gas contains carbon dioxide and hydrogen, and converting at least a portion of the feed gas to carbon monoxide involves subjecting the feed gas to a reverse water-gas shift reaction. The reverse water-gas shift reaction is particularly suitable for converting at least a portion of the feed gas to carbon monoxide. At least a portion of the hydrogen may remain in the synthesis gas, i.e., it is not converted to water in the reverse water-gas shift reaction. This makes it possible to use it in the subsequent Fischer-Tropsch reaction. Since the reverse water-gas shift reaction uses carbon dioxide, carbon dioxide produced by combustion can be used, otherwise carbon dioxide may be released into the atmosphere.

[0030] The reverse water-gas shift reaction is preferably an autothermal reverse water-gas shift reaction, an electroheated reverse water-gas shift reaction, or a plasma-heated reverse water-gas shift reaction. Such reactions are particularly suitable.

[0031] The reverse water-gas shift reaction is preferably carried out using a catalyst containing nickel, more preferably the catalyst contains 3 to 20% by weight of nickel, expressed as NiO, on a refractory metal oxide support, based on the total weight of the reverse water-gas shift catalyst. Such a catalyst can enable the reverse water-gas shift reaction to be carried out at reduced temperature and / or pressure, and / or with high yield and / or high selectivity. Furthermore, such a catalyst is active for the conversion of carbon-containing substances in the second stripper exhaust vapor into synthesis gas by steam reforming.

[0032] The reverse water-gas shift reaction is preferably carried out at a temperature of at least 700°C. Such temperatures can yield particularly high yields.

[0033] In another configuration, the feed gas includes methane and steam, and converting at least a portion of the feed gas to carbon monoxide involves subjecting the feed gas to a steam reforming reaction. The steam reforming reaction is particularly suitable for converting at least a portion of the feed gas to carbon monoxide.

[0034] The steam reforming reaction is preferably carried out using a catalyst containing nickel.

[0035] Steam reforming is preferably carried out at a pressure of 15 to 55 bara and / or a temperature of 750 to 1100°C. Such conditions can yield particularly high yields and / or selectivity.

[0036] The steam reforming reaction preferably includes one or more steps from adiabatic steam reforming, combustion steam reforming, gas-heated reforming, electric-heated reforming, and autoheated steam reforming.

[0037] Preferably, the mass (or molar) ratio of vapor to aqueous condensate in the first stripper is 0.1:1 to 0.5:1, more preferably 0.2:1 to 0.4:1, even more preferably 0.25:1 to 0.35:1, and even more preferably about 0.3:1. Lower levels of vapor can result in a less efficient stripping process. Higher levels of vapor can increase the cost of the method without any significant increase in the efficiency of the stripping process.

[0038] By operating the first stripper within the above range, the mass (or molar) ratio of the first stripper exhaust steam to the production-associated water in the second stripper may be 0.2:1 to 0.6:1, preferably 0.3:1 to 0.5:1, more preferably 0.35:1 to 0.45:1, and even more preferably about 0.4:1. Lower levels of the first stripper exhaust steam can result in a less efficient stripping treatment. Higher levels of the first stripper exhaust steam can increase the cost of the method without any significant increase in the efficiency of the stripping treatment.

[0039] The first stripper preferably operates at a higher pressure than the second stripper. More preferably, the first stripper operates at a pressure 100-200 kPa higher than the pressure of the second stripper. This may make it easier to pass the exhaust steam from the first stripper to the second stripper due to any pressure drop that may occur in the first stripper.

[0040] The first and second strippers are preferably operated at a pressure of 1500–5500 kPa. Such pressures may be particularly suitable for transferring carbon-containing gases from aqueous condensate to vapor and / or carbon-containing substances from production-associated water to the first stripper exhaust vapor. Furthermore, using such pressures brings the second stripper exhaust vapor to a pressure suitable for incorporation into the feed gas without requiring a substantial pressurization step that would reduce the energy efficiency of the method. When synthesis gas is generated using a reverse water-gas shift reaction, it is preferable to use lower pressures such as 1500–3000 kPa. When synthesis gas is produced using a steam reforming reaction, it is preferable to use higher pressures such as 3000–5500 kPa.

[0041] The method may further include passing the stripped aqueous condensate through a demineralization plant to produce water for generating steam. Since the stripped aqueous condensate tends to be relatively "clean," it can be sent to the demineralization plant without substantial pretreatment. The generated steam is preferably used in the first stripper, or for heat exchange with the components of the feed gas, or for heat exchange within the Fischer-Tropsch unit.

[0042] The method may further include a step of passing the stripped production-associated water through a water treatment unit to generate a water discharge stream. Such a water discharge stream can be sufficiently "clean" for subsequent disposal.

[0043] The carbon-containing gas dissolved in the aqueous condensate and / or the carbon-containing substances dissolved in the production-associated water preferably include carbon dioxide and / or carbon monoxide and / or organic compounds (e.g., water-soluble organic compounds). Since such species can be used in the synthesis gas production process, it may be beneficial to recirculate such species in the second stripper exhaust steam. For example, such species are typically converted into synthesis gas in a reverse water-gas shift unit or a steam reforming unit.

[0044] The molar ratio of hydrogen to carbon monoxide in the water-removed synthesis gas is preferably 1.8 to 2.2. This ratio is particularly suitable for the subsequent Fischer-Tropsch reaction.

[0045] The Fischer-Tropsch unit preferably operates at a temperature of 150°C to 300°C. Lower temperatures may result in undesirably low levels of liquid hydrocarbons being produced. Higher temperatures may increase the energy cost of the method and increase the formation of unwanted by-products, without significantly increasing the level of liquid hydrocarbons produced.

[0046] The Fischer-Tropsch unit preferably comprises a catalyst containing cobalt, iron, and / or ruthenium, preferably cobalt. Such catalysts are particularly effective as catalysts for the Fischer-Tropsch reaction and / or can favorably carry out the reaction to alkanes at low temperatures and / or in high yield.

[0047] The liquid hydrocarbon product preferably contains an alkane. The alkane may be a particularly desirable product.

[0048] One or more compounds in the supply gas may be derived from the gasification of biomass and / or municipal waste.

[0049] In a preferred embodiment, the second stripper exhaust vapor may be directly recirculated into the feed gas. In other words, the second stripper exhaust vapor may be recirculated into the feed gas without any substantial further processing steps. In another preferred embodiment, before recirculating the second stripper exhaust vapor into the feed gas, it may be passed through a removal and conversion reactor to convert hydrocarbons having two or more carbon atoms contained in the second stripper exhaust vapor into methane. Methane may be more readily converted to carbon monoxide in the synthesis gas production process.

[0050] Next, the present invention will be described with reference to the figures. Those skilled in the art will understand that the drawings are schematic and that in a commercial plant, further items of equipment may be required, such as raw material drums, pumps, vacuum pumps, compressors, gas recirculation compressors, temperature sensors, pressure sensors, pressure relief valves, control valves, flow controllers, level controllers, holding tanks, and storage tanks.

[0051] Referring to Figure 1, the aqueous process condensate stream 10 recovered from the synthesis gas generation unit (not shown) is first heated in the heat exchanger 12 by exchange with the bottom liquid of the process condensate stripper from line 14 and supplied via line 16 to near the top of the first stripper 18. The first stripper contains structured packing to facilitate the removal of dissolved gases from the aqueous process condensate. The heated process condensate passes downward through the first stripper 18, where it comes into contact with high-pressure steam supplied via line 20 to near the bottom of the first stripper. The high-pressure steam strips away carbon-containing gases from the heated process condensate. The stripped liquid process condensate stream 14 recovered from the bottom of the first stripper 18 is first cooled in the heat exchanger 12 by exchange with the first stripper feed for delivery to the water treatment unit (not shown), and then cooled in one or more further heat exchangers 22 to cooling water or air. The stripped aqueous condensate may be supplied to a demineralized water unit for purification and process use. The first stripper exhaust steam is recovered from the top of the first stripper 18 and supplied via line 24 to near the bottom of the second stripper 26. The Fischer-Tropsch production associated water flow from a Fischer-Tropsch synthesis unit (not shown), supplied by line 28, is first heated in a heat exchanger 30 by exchange with the bottom liquid of the second stripper from line 32 and supplied via line 34 to near the top of the second stripper 26. A bypass 36 around the heat exchanger 30 is used to control the inlet temperature to the second stripper 26. The second stripper contains structured packing to facilitate the removal of dissolved substances from the production associated water. The heated production associated water passes downward through the second stripper 26, where it comes into contact with the first stripper exhaust steam supplied via line 24. The first stripper discharge vapor is used to strip carbon-containing substances from the production-associated water.The stripped production-associated water flow 32 is first cooled by being exchanged for the second stripper feed in an exchanger 30, and then cooled to cooling water or air in one or more further heat exchangers 38 for delivery to a water treatment unit (not shown) for further purification. The second stripper exhaust steam containing carbon-containing material is recovered from the top of the second stripper 26 and supplied via line 40 to a synthesis gas production unit (not shown), and is recirculated as the synthesis gas production unit supply gas.

[0052] Referring to Figure 2, an embodiment similar to the embodiment in Figure 1 is shown. However, in the embodiment in Figure 2, the bypass 36 is omitted, and the heat exchanger 50 and gas-liquid separator 52 are used to condense a portion of the second stripper exhaust steam and separate the stripper exhaust condensate, which is returned to the vicinity of the top of the second stripper 26 via a pump through line 54. The remaining second stripper exhaust steam is recovered from the gas-liquid separator 52 and supplied via line 56 to a synthesis gas generation unit (not shown) and recirculated as the synthesis gas generation unit supply gas.

[0053] The method according to the present invention enables a higher recovery rate of carbon-containing material from aqueous streams than alternative methods using a single stripper or two strippers operating in parallel.

[0054] Next, the present invention will be described in relation to the following non-limiting examples and comparative examples. [Examples]

[0055] The process shown in Figure 1 is designed to provide a vapor flow to a removal and conversion vessel in an upstream synthesis gas production unit. In the synthesis gas production unit, the removal and conversion vessel supplies a feed containing carbon dioxide, hydrogen, and methane to an autothermally heated reverse water-gas shift reactor (rWGS unit) operating at approximately 30 bara, which provides synthesis gas containing carbon monoxide and hydrogen for use in the Fischer-Tropsch synthesis reaction to produce liquid hydrocarbons after separation of aqueous condensate. The Fischer-Tropsch reaction produces a flow of production-associated water as a byproduct.

[0056] The ratio of water vapor to aqueous condensate used in the first stripper was 0.3:1. The applicant found it beneficial to maximize water vapor carryover from the first stripper, as this reduces the chemical oxygen demand (COD) of the stripped aqueous condensate, thereby reducing water treatment requirements, and also has a dilution effect on contaminants in the stripped Fischer-Tropsch production associated water stream. This may be achieved by maximizing the amount of heat transferred in the heat exchanger 12 by using a low hot-end temperature approach, e.g., about 35°C. The outlet temperature from the heat exchanger 30, which sets the production associated water temperature to the second stripper, was adjusted so that the overhead rate from the second stripper was equal to about 90% of the steam addition required upstream of the removal vessel. This allowed for the addition of 10% direct steam to the concentration vessel for further controllability. Typical specifications of the untreated aqueous condensate stream are as follows:

[0057] [Table 1]

[0058] The typical specifications for untreated production-associated water flow are as follows:

[0059] [Table 2]

[0060] By using high-pressure steam supplied by the rWGS unit at a saturated steam of 50 bara, a steam-to-condensate ratio of 0.3:1 to the first stripper, and an inlet aqueous condensate temperature of 200°C (equivalent to a 35°C approach in the heat exchanger), an inlet temperature of production-produced water to the second stripper of 145°C (equivalent to a 90°C approach) is obtained, thereby yielding a suitable amount of steam for the removal-conversion vessel. This results in the following outcomes with respect to aqueous condensate, production-produced water, and process carbon efficiency (compared to not recovering carbon from the condensate flow by stripping):

[0061] [Table 3]

[0062] Comparative Example By comparison, to illustrate the improvements of the present invention that enable integration with the same rWGS unit, stripping could instead be carried out in two parallel stripping towers. By setting the approach in both heat exchangers to 35°C to minimize steam addition and adjusting the steam-to-condensate ratio in each tower to achieve similar COD reduction, the following results are obtained (compared to no carbon being recovered from the condensate flow by the stripping process):

[0063] [Table 4]

[0064] Since the majority of organic compounds are contained in the production-associated water stripper overhead, the penalty to carbon efficiency is minimal. However, the total overhead steam generated from both strippers accounts for 370% of the process requirements, meaning that the remainder of the steam must be condensed and sent to the water treatment. Thus, the use of steam, energy, and carbon is far less efficient than in the present invention. Furthermore, the two-stage series arrangement allows the same steam to be effectively used in both stripping treatment towers when the stripping load in the first tower is much lighter than that of the second tower.

[0065] The detailed description above is provided for illustrative and illustrative purposes only and is not intended to limit the scope of the appended claims. Many modifications of the currently preferred embodiments shown herein will be obvious to those skilled in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. A method for forming a liquid hydrocarbon product, wherein the method is To provide a supply gas containing compounds of carbon, hydrogen, and oxygen elements, The process involves generating synthesis gas from the aforementioned supply gas, wherein the synthesis gas contains carbon monoxide, hydrogen, and water vapor. The synthesis gas is cooled to below its dew point to form an aqueous condensate and a water-removed synthesis gas, wherein the aqueous condensate contains a carbon-containing gas dissolved therein. The aqueous condensate is passed through a first stripper, and the aqueous condensate is stripped with steam to transfer the carbon-containing gas from the aqueous condensate to the steam, thereby forming the stripped aqueous condensate and the steam discharged from the first stripper. The water-removed synthesis gas is passed through a Fischer-Tropsch unit to form a liquid hydrocarbon product and associated water, wherein the associated water contains dissolved carbon-containing substances. The production-associated water is passed through a second stripper, and the production-associated water is stripped with the first stripper discharge steam to transfer carbon-containing substances from the production-associated water to the first stripper discharge steam, thereby forming stripped production-associated water and second stripper discharge steam. A method comprising recirculating the second stripper exhaust steam into the supply gas.

2. The method according to claim 1, wherein generating synthesis gas from the supply gas includes converting at least a portion of the supply gas into carbon monoxide.

3. The supply gas contains carbon dioxide and hydrogen. The method according to claim 2, wherein converting at least a portion of the supply gas to carbon monoxide is performed by subjecting the supply gas to a reverse water-gas shift reaction.

4. The method according to claim 3, wherein the reverse water-gas shift reaction is an autothermal reverse water-gas shift reaction, an electrically heated reverse water-gas shift reaction, or a plasma heated reverse water-gas shift reaction.

5. The method according to claim 3 or 4, wherein the reverse water-gas shift reaction is carried out using a catalyst containing nickel, preferably the 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.

6. The method according to any one of claims 3 to 5, wherein the reverse water-gas shift reaction is carried out at a temperature of at least 700°C.

7. The supply gas includes methane and water vapor. The method according to claim 2, wherein converting at least a portion of the supply gas to carbon monoxide is further comprising subjecting the supply gas to a steam reforming reaction.

8. The method according to claim 7, wherein the steam reforming reaction is carried out using a catalyst containing nickel.

9. The method according to claim 7 or 8, wherein the steam reforming is carried out at a pressure of 15 to 55 bara and / or at a temperature of 750 to 1100°C.

10. The method according to any one of claims 7 to 9, wherein the steam reforming reaction comprises one or more steps from adiabatic steam reforming, combustion steam reforming, gas-heated reforming, electric-heated reforming, and autoheated steam reforming.

11. The method according to any one of claims 1 to 10, wherein the mass ratio of vapor to aqueous condensate in the first stripper is 0.1:1 to 0.5:1, preferably 0.2:1 to 0.4:1, more preferably 0.25:1 to 0.35:1, and even more preferably about 0.3:

1.

12. The method according to any one of claims 1 to 11, wherein the mass ratio of the first stripper discharge liquid to the production associated water in the second stripper is 0.2:1 to 0.6:1, preferably 0.3:1 to 0.5:1, more preferably 0.35:1 to 0.45:1, and even more preferably about 0.4:

1.

13. The method according to any one of claims 1 to 12, wherein the first stripper operates at a higher pressure than the second stripper.

14. The method according to claim 13, wherein the first stripper operates at a pressure 100 to 200 kPa higher than the pressure of the second stripper.

15. The method according to any one of claims 1 to 14, wherein the first stripper and the second stripper operate at a pressure of 1500 to 5500 kPa.

16. The method according to any one of claims 1 to 15, further comprising passing the stripped aqueous condensate through a demineralized water plant to generate water for generating steam, preferably the steam being used in the first stripper.

17. The method according to any one of claims 1 to 16, further comprising passing the stripped production-associated water through a water treatment unit to generate a water discharge flow.

18. The method according to any one of claims 1 to 17, wherein the carbon-containing gas dissolved in the aqueous condensate and / or the carbon-containing substance dissolved in the production-associated water comprises carbon dioxide and / or carbon monoxide and / or a water-soluble organic compound.

19. The method according to any one of claims 1 to 18, wherein the molar ratio of hydrogen to carbon monoxide in the water-removed synthesis gas is 1.8 to 2.

2.

20. The method according to any one of claims 1 to 19, wherein the Fischer-Tropsch unit operates at a temperature of 150°C to 300°C.

21. The method according to any one of claims 1 to 20, wherein the Fischer-Tropsch unit comprises a catalyst containing cobalt, iron, and / or ruthenium, preferably cobalt.

22. The method according to any one of claims 1 to 21, wherein the liquid hydrocarbon product comprises an alkane.

23. The method according to any one of claims 1 to 22, wherein one or more of the compounds in the supply gas are derived from the gasification of biomass and / or municipal waste.

24. The method according to any one of claims 1 to 23, wherein, before recirculating the second stripper exhaust vapor into the supply gas, the second stripper exhaust vapor is passed through a concentration reduction reactor to convert the hydrocarbons contained in the second stripper exhaust vapor into methane.

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