Olefin production system and olefin production method

Abstract

An olefin production system (1) comprises: a reactor (10) that generates water and a hydrocarbon, which contains a lower olefin, from a feedstock containing hydrogen and carbon dioxide and / or carbon monoxide; a first gas-liquid separation tank (20) that separates the product generated by the reactor (10) into a gas containing the lower olefin and a liquid containing water and a hydrocarbon that contains the lower olefin; and a second gas-liquid separation tank (30) that is connected to the first gas-liquid separation tank (20) and separates the gas containing the lower olefin from the liquid transferred from the first gas-liquid separation tank (20). The lower olefin contains at least one substance selected from the group consisting of ethylene, propylene, butene and butadiene.

Description

Olefin production system and olefin production method

[0001] The present disclosure relates to an olefin production system and method.

[0002] Carbon dioxide is considered a problematic cause of global warming, and there has been a growing global movement to curb carbon dioxide emissions. By producing methane from carbon dioxide contained in exhaust gases from factories, it is possible to curb carbon dioxide emissions and produce valuable methane. Methane can also be produced not only from raw materials containing carbon dioxide, but also from raw materials containing carbon monoxide, which is contained in the combustion gases of hydrocarbons contained in factory exhaust gases, biomass, and waste.

[0003] On the other hand, hydrocarbons containing lower olefins such as ethylene and propylene, which are used as raw materials for plastics or resins, are traded at higher prices than methane and can be produced from raw materials containing carbon dioxide or carbon monoxide. Furthermore, producing plastics or resins from carbon dioxide reduces carbon dioxide emissions into the atmosphere and provides carbon-neutral plastics or resins. Patent Document 1 discloses a process for producing hydrocarbons containing lower olefins from raw materials containing carbon monoxide and hydrogen.

[0004] International Publication No. 2020 / 116478

[0005] However, in a reaction for producing lower olefins from a raw material containing carbon dioxide or carbon monoxide, liquid hydrocarbons with long carbon chains are simultaneously produced in addition to the lower olefins. The product obtained as a liquid containing water is recovered in a drain tank, but the lower olefins dissolve in the liquid. This results in a low yield of the product obtained as a gas containing lower olefins. Patent Document 1 has a configuration for separating the produced gas and liquid and a configuration for separating water from the produced liquid, but does not recover the lower olefins dissolved in water. Therefore, it was an issue to construct a lower olefin production system that improves the yield of lower olefins.

[0006] An object of the present disclosure is to provide an olefin production system and an olefin production method that improve the yield of lower olefins in a reaction using a raw material containing at least one of carbon dioxide and carbon monoxide.

[0007] The olefin production system according to the present disclosure includes a reactor that produces hydrocarbons containing lower olefins and water from a feedstock containing at least one of carbon dioxide and carbon monoxide and hydrogen. The olefin production system also includes a first gas-liquid separation tank that separates the product produced in the reactor into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The olefin production system also includes a second gas-liquid separation tank connected to the first gas-liquid separation tank that separates the gas containing lower olefins from the liquid transferred from the first gas-liquid separation tank. The lower olefins include at least one selected from the group consisting of ethylene, propylene, butene, and butadiene.

[0008] The olefin production system may include a cooler that cools the product produced in the reactor, and the first gas-liquid separation tank may separate the product cooled in the cooler into gas and liquid.

[0009] The pressure in the second separation tank may be lower than the pressure in the first gas-liquid separation tank.

[0010] The olefin production system may include a pressure control valve installed between the first gas-liquid separation tank and the second gas-liquid separation tank, which controls the pressure of the second gas-liquid separation tank to be lower than the pressure of the first gas-liquid separation tank.

[0011] The second gas-liquid separation tank may be capable of being heated.

[0012] The olefin production system may include a plurality of olefin production apparatuses connected in series, each including a reactor, a cooler, and a first gas-liquid separation tank, and liquid transferred from two or more of the plurality of first gas-liquid separation tanks included in the plurality of olefin production apparatuses may be collected in a second gas-liquid separation tank.

[0013] The olefin production method according to the present disclosure includes an olefin production step of producing hydrocarbons containing lower olefins and water from a feedstock containing at least one of carbon dioxide and carbon monoxide and hydrogen in a reactor. The olefin production method also includes a gas-liquid separation step of cooling the product obtained in the olefin production step in a cooler and then separating the product in a first gas-liquid separation tank into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The olefin production method also includes a transfer step of transferring the gas and liquid obtained in the gas-liquid separation step to a second gas-liquid separation tank, and an olefin separation step of separating lower olefins from the liquid transferred to the second gas-liquid separation tank in the transfer step.

[0014] According to the present disclosure, it is possible to provide an olefin production system and an olefin production method that improve the yield of lower olefins in a reaction using a raw material containing at least one of carbon dioxide and carbon monoxide.

[0015]

[0013] Figure 1 is a schematic diagram showing an olefin production system according to one embodiment. Figure 2 is a schematic diagram showing an olefin production system according to another embodiment.

[0016] Hereinafter, several exemplary embodiments will be described with reference to the drawings. Note that the dimensional proportions of the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0017] First Embodiment First, an olefin production system 1 according to a first embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the olefin production system 1 according to this embodiment includes a reactor 10, a first gas-liquid separation tank 20, and a second gas-liquid separation tank 30. The olefin production system 1 may further include a cooler 40, a pressure control valve 50, a first flow control valve 60, and a second flow control valve 61. Note that the term "olefin" refers to an alkene.

[0018] The reactor 10 produces hydrocarbons containing lower olefins and water from a raw material containing at least one of carbon dioxide and carbon monoxide, and hydrogen. In the reactor 10, for example, a catalyst is disposed in a flow path through which the raw material passes, and the raw material comes into contact with the catalyst to produce hydrocarbons containing lower olefins and water. The temperature conditions in the reactor 10 are not particularly limited, but for example, the reaction temperature is preferably 200°C to 400°C, more preferably 250 to 350°C, and even more preferably 270 to 330°C. The pressure conditions in the reactor 10 are also not particularly limited, but for example, the pressure is preferably 1.0 MPa to 3.0 MPa, and more preferably 1.2 MPa to 2.0 MPa.

[0019] In the reactor 10, the reaction represented by the following reaction formula (1) proceeds when the raw material contains carbon dioxide, and the reaction represented by the following reaction formula (2) proceeds when the raw material contains carbon monoxide. At least one of carbon dioxide and carbon monoxide reacts with hydrogen to produce hydrocarbons including lower olefins and water. The reactions represented by the reaction formulas (1) and (2) are generally called Fischer-Tropsch reactions (FT reactions). For the reactor 10, a known reactor may be used, including, for example, a multi-tubular reactor such as a shell-and-tube reactor, a fluidized bed reactor, or a slurry bed reactor. nCO ２ +3nH ２ →-(CH ２ ) ｎ -+2nH ２ O (1) nCO+2nH ２ →-(CH ２ ) ｎ - + nH ２ O (2)

[0020] The lower olefins contained in the hydrocarbons produced in the reactor 10 include at least one selected from the group consisting of ethylene, propylene, butene, and butadiene. Specifically, lower olefins include olefins having 2 to 4 carbon atoms, such as ethylene, propylene, 1-butene, 2-butene, isobutene, and 1,3-butadiene. Such olefins having 2 to 4 carbon atoms are useful as raw materials for plastics. The hydrocarbons produced in the reactor 10 may contain not only lower olefins but also hydrocarbons other than lower olefins. Hydrocarbons other than lower olefins include, for example, paraffins having 2 to 4 carbon atoms, and paraffins and olefins having 5 or more carbon atoms. Note that paraffins refer to alkanes.

[0021] Carbon dioxide contained in the raw material used in the reactor 10 may be supplied to the reactor 10 from a carbon dioxide supply unit (not shown). The carbon dioxide supply unit may include a carbon dioxide capture unit that captures carbon dioxide emitted from a carbon dioxide generation source such as a power plant or a factory. By using carbon dioxide captured from the carbon dioxide generation source as the raw material, the amount of carbon dioxide released into the atmosphere can be reduced. The carbon dioxide capture unit may capture carbon dioxide by, for example, chemical absorption, pressure swing adsorption, temperature swing adsorption, membrane separation concentration, or a combination of these. Note that the carbon dioxide supply unit is not limited to the above-mentioned form and may be, for example, a tank containing carbon dioxide, a cylinder, or a carbon dioxide gas generator.

[0022] Carbon monoxide contained in the raw material used in the reactor 10 may be supplied to the reactor 10 from a carbon monoxide supply unit (not shown). The carbon monoxide supply unit may be, for example, a tank, a cylinder, or a carbon monoxide gas generator that stores carbon monoxide. Alternatively, carbon monoxide may be generated from carbon dioxide and supplied to the reactor 10. For example, carbon dioxide, methane, and steam may be reacted under a pressure of about 2 MPa and a temperature of about 1100°C in a reformer (not shown) that reforms carbon monoxide into carbon monoxide and hydrogen, and the generated carbon monoxide may be cooled and then supplied to the reactor 10.

[0023] The hydrogen contained in the raw material used in the reactor 10 may be supplied to the reactor 10 from a hydrogen supply unit (not shown). The hydrogen supply unit may use hydrogen obtained by electrolyzing water using renewable energy such as solar, wind, or hydropower. By using such hydrogen, the olefin production system 1 as a whole can reduce carbon dioxide emissions. The hydrogen supply unit is not limited to the above-mentioned form and may be, for example, a tank containing hydrogen, a cylinder, or a hydrogen gas generator.

[0024] In the above embodiment, the raw materials are supplied to the reactor 10 by at least one of the carbon dioxide supply unit and the carbon monoxide supply unit and the hydrogen supply unit. However, the mixed raw materials may be stored in a tank, and the mixed raw materials may be supplied from the tank to the reactor 10.

[0025] The catalyst used in the reactor 10 is not particularly limited, and known catalysts such as iron catalysts or cobalt catalysts can be used. The iron catalyst can mainly produce olefins and paraffins, while the cobalt catalyst can mainly produce paraffins. The iron catalyst is a catalyst containing iron as an active component, and the cobalt catalyst is a catalyst containing cobalt as an active component. The content of the active component is preferably 10 mass% or more of the total catalyst. From the viewpoint of facilitating the production of lower olefins, the catalyst used in the reactor 10 may be an iron catalyst.

[0026] The product produced in the reactor 10 is supplied as a gas or liquid to the first gas-liquid separation tank 20 in a pressurized state, similar to the reactor 10. The gas supplied from the reactor 10 to the first gas-liquid separation tank 20 may contain at least one of unreacted carbon dioxide and carbon monoxide.

[0027] The first gas-liquid separation tank 20 separates the product produced in the reactor 10 into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. Since the inside of the first gas-liquid separation tank 20 is pressurized, some of the lower olefins are in a gaseous state, and some of the lower olefins are dissolved in water and contained in the liquid.

[0028] The temperature conditions in the first gas-liquid separation tank 20 are not particularly limited, but are preferably, for example, 20° C. to 30° C. Furthermore, the pressure conditions in the first gas-liquid separation tank 20 are not particularly limited, but are preferably, for example, the same as the pressure conditions in the reactor 10.

[0029] A cooler 40 may be provided in the flow path connecting the reactor 10 and the first gas-liquid separation tank 20. That is, the cooler 40 may be provided to cool the product produced in the reactor 10, and the first gas-liquid separation tank 20 may separate the product cooled in the cooler 40 into gas and liquid. By providing the cooler 40, the product produced in the reactor 10 can be quickly cooled and supplied to the first gas-liquid separation tank 20, thereby improving the efficiency of the production process.

[0030] The gas containing lower olefins separated in the first gas-liquid separation tank 20 is transferred to the second gas-liquid separation tank 30. On the other hand, the liquid containing hydrocarbons containing lower olefins and water separated in the first gas-liquid separation tank 20 is transferred to the second gas-liquid separation tank 30 via a flow path separate from that for the gas containing lower olefins. That is, as shown in Figure 1, the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30 are connected by two types of flow paths, upper and lower, and the gas and liquid are transferred separately. In Figure 1, of the flow paths connecting the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30, the upper side is the flow path for gas and the lower side is the flow path for liquid.

[0031] The second gas-liquid separation tank 30 is connected to the first gas-liquid separation tank 20 and separates gas containing lower olefins from the liquid transferred from the first gas-liquid separation tank 20. In order to release the lower olefins dissolved in water in the first gas-liquid separation tank 20 into the second gas-liquid separation tank 30, the pressure in the second gas-liquid separation tank 30 is preferably lower than the pressure in the first gas-liquid separation tank 20, and it is more preferable that the pressure inside the second gas-liquid separation tank 30 is normal. In this way, the second gas-liquid separation tank 30 can release and separate the lower olefins dissolved in water by utilizing the pressure difference with the pressurized first gas-liquid separation tank 20.

[0032] A pressure control valve 50 may be provided in the gas flow path connecting the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30. That is, the pressure control valve 50 may be installed between the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30 and control the pressure of the second gas-liquid separation tank 30 to be lower than the pressure of the first gas-liquid separation tank 20. By providing the pressure control valve 50, the pressure in the gas flow path can be controlled so that the pressure on the right side of the dotted line L in FIG. 1 is lower than the pressure on the left side of the dotted line L. As a result, the pressure in the second gas-liquid separation tank 30 is lower than the pressure in the first gas-liquid separation tank 20. The pressure control valve 50 is not particularly limited as long as it can control pressure, and examples thereof include a back pressure valve, a pressure reducing valve, and a relief valve.

[0033] A first flow control valve 60 may be provided in the liquid flow path connecting the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30. Specifically, the amount of liquid in the first gas-liquid separation tank 20 may be managed using a water level gauge or the like, and after a certain amount of liquid has accumulated in the first gas-liquid separation tank 20, the first flow control valve 60 may be opened to transfer the liquid from the first gas-liquid separation tank 20 to the second gas-liquid separation tank 30. In this way, by managing the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30 so that a certain amount of liquid is always maintained, it becomes easier to control the pressure in the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30. The first flow control valve 60 is not particularly limited as long as it can control the flow rate of the liquid.

[0034] The second gas-liquid separation tank 30 is preferably capable of being heated, and more preferably capable of being heated to 30 to 40° C. Heating the second gas-liquid separation tank 30 under such conditions can promote the release of lower olefins dissolved in water.

[0035] The lower olefins released from the liquid in the second gas-liquid separation tank 30 are combined with the gas containing lower olefins transferred from the first gas-liquid separation tank 20 to the second gas-liquid separation tank 30 and are recovered through the flow path 70. In this way, the gas containing lower olefins is separated and recovered in two stages, in the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30, thereby improving the yield of lower olefins. The recovered gas containing lower olefins is supplied to a downstream process such as a carbon dioxide absorption tower or a separation device.

[0036] On the other hand, the liquid remaining in the second gas-liquid separation tank 30 after the lower olefins have been released is released from the second gas-liquid separation tank 30 by the second flow control valve 61, thereby adjusting the amount of liquid in the second gas-liquid separation tank 30.

[0037] As described above, the olefin production system 1 according to this embodiment includes a reactor 10 that produces hydrocarbons containing lower olefins and water from a raw material containing at least one of carbon dioxide and carbon monoxide, and hydrogen. The olefin production system 1 also includes a first gas-liquid separation tank 20 that separates the product produced in the reactor 10 into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The olefin production system 1 also includes a second gas-liquid separation tank 30 that is connected to the first gas-liquid separation tank 20 and separates the gas containing lower olefins from the liquid transferred from the first gas-liquid separation tank 20. The lower olefins include at least one selected from the group consisting of ethylene, propylene, butene, and butadiene. Therefore, an olefin production system can be provided that improves the yield of lower olefins in a reaction using a raw material containing at least one of carbon dioxide and carbon monoxide.

[0038] Next, an olefin production method using the olefin production system 1 will be described. The olefin production method includes an olefin production step of producing hydrocarbons including lower olefins and water from a feedstock containing at least one of carbon dioxide and carbon monoxide and hydrogen in a reactor 10. As described above, in the reactor 10, the reaction represented by reaction formula (1) proceeds when the feedstock contains carbon dioxide, and the reaction represented by reaction formula (2) proceeds when the feedstock contains carbon monoxide, and at least one of carbon dioxide and carbon monoxide reacts with hydrogen to produce hydrocarbons including lower olefins and water.

[0039] The olefin production method includes a gas-liquid separation step in which the product obtained in the olefin production step is cooled in a cooler and then separated into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water in the first gas-liquid separation tank 20. As described above, the inside of the first gas-liquid separation tank 20 is pressurized, so that part of the lower olefins is in a gaseous state and part of the lower olefins is dissolved in water and contained in the liquid.

[0040] The olefin production method includes a transfer step of transferring the gas and liquid obtained in the gas-liquid separation step to the second gas-liquid separation tank 30. As described above, the gas containing lower olefins separated in the first gas-liquid separation tank 20 is transferred to the second gas-liquid separation tank 30. On the other hand, the hydrocarbons containing lower olefins and the liquid containing water separated in the first gas-liquid separation tank 20 are transferred to the second gas-liquid separation tank 30 via a flow path separate from that for the gas containing lower olefins.

[0041] The olefin production method includes an olefin separation step of separating lower olefins from the liquid transferred to the second gas-liquid separation tank 30 in the transfer step. As described above, in the second gas-liquid separation tank 30, the pressure difference between the first gas-liquid separation tank 20, which is pressurized, is utilized to release the lower olefins dissolved in water in the first gas-liquid separation tank 20 into the second gas-liquid separation tank 30, thereby separating the lower olefins. In this way, by separating and recovering the gas containing lower olefins in two stages, in the first gas-liquid separation tank 20 and the second gas-liquid separation tank 30, the yield of lower olefins can be improved.

[0042] As described above, the olefin production method using the olefin production system 1 includes an olefin production step of producing hydrocarbons containing lower olefins and water from a raw material containing at least one of carbon dioxide and carbon monoxide and hydrogen in the reactor 10. The olefin production method also includes a gas-liquid separation step of cooling the product obtained in the olefin production step in a cooler 40 and then separating the product in a first gas-liquid separation tank 20 into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The olefin production method also includes a transfer step of transferring the gas and liquid obtained in the gas-liquid separation step to a second gas-liquid separation tank 30, and an olefin separation step of separating lower olefins from the liquid transferred to the second gas-liquid separation tank 30 in the transfer step. Therefore, it is possible to provide an olefin production method that improves the yield of lower olefins in a reaction using a raw material containing at least one of carbon dioxide and carbon monoxide.

[0043] Second Embodiment Next, an olefin production system 1a according to a second embodiment will be described with reference to Fig. 2. In the description of the second embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.

[0044] The olefin production system 1a of the second embodiment corresponds to the olefin production system 1 of the first embodiment. The reactors 10a, 10b, and 10c of the second embodiment correspond to the reactor 10 of the first embodiment. The coolers 40a, 40b, and 40c of the second embodiment correspond to the cooler 40 of the first embodiment. Furthermore, the first gas-liquid separation tanks 20a, 20b, and 20c of the second embodiment correspond to the first gas-liquid separation tank 20 of the first embodiment.

[0045] As shown in FIG. 2, the olefin production system 1a according to this embodiment includes reactors 10a, 10b, and 10c, coolers 40a, 40b, and 40c, and first gas-liquid separation tanks 20a, 20b, and 20c, and may include multiple olefin production apparatuses 80a, 80b, and 80c connected in series. As shown by the dotted lines in FIG. 2, the olefin production apparatuses 80a, 80b, and 80c each include the reactors 10a, 10b, and 10c, the coolers 40a, 40b, and 40c, and the first gas-liquid separation tanks 20a, 20b, and 20c. The number of stages of the olefin production apparatus in the olefin production system is set with one olefin production apparatus as a unit. Therefore, the olefin production system 1a in FIG. 2 includes three olefin production apparatuses 80a, 80b, and 80c. The number of stages of the olefin production apparatus is not particularly limited and may be two stages or four or more stages.

[0046] Furthermore, liquid transferred from two or more first gas-liquid separation tanks 20 among the plurality of first gas-liquid separation tanks 20a, 20b, 20c included in the plurality of olefin production apparatuses 80a, 80b, 80c may be collected in the second gas-liquid separation tank 30 via the first flow control valves 60a, 60b, 60c. Although three reactors 10, coolers 40, first gas-liquid separation tanks 20, and first flow control valves 60 are installed in FIG. 2, two or four or more of each may be installed. Furthermore, the numbers of reactors 10, coolers 40, first gas-liquid separation tanks 20, and first flow control valves 60 installed in each olefin production apparatus do not necessarily have to be the same, and may be different. Furthermore, it is not necessary for all of the first gas-liquid separation tanks 20 to be connected to the second gas-liquid separation tank 30, and some of the first gas-liquid separation tanks 20a, 20b, 20c included in the olefin production system 1a may be connected to the second gas-liquid separation tank 30.

[0047] The first gas-liquid separation tank 20a separates the product produced in the reactor 10a and cooled in the cooler 40a into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The gas containing lower olefins separated in the first gas-liquid separation tank 20a also contains raw material containing unreacted carbon dioxide and / or carbon monoxide, and hydrogen. Therefore, in the reactor 10b, hydrocarbons containing lower olefins and water can be produced from the raw material containing unreacted carbon dioxide and / or carbon monoxide, and hydrogen.

[0048] The first gas-liquid separation tank 20b separates the product produced in the reactor 10b and cooled in the cooler 40b into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The gas containing lower olefins separated in the first gas-liquid separation tank 20b also contains raw material containing unreacted carbon dioxide and / or carbon monoxide, and hydrogen. Therefore, in the reactor 10c, hydrocarbons containing lower olefins and water can be produced from the raw material containing unreacted carbon dioxide and / or carbon monoxide, and hydrogen.

[0049] The first gas-liquid separation tank 20c separates the product produced in the reactor 10c and cooled in the cooler 40c into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water. The gas containing lower olefins separated in the first gas-liquid separation tank 20c is transferred to the second gas-liquid separation tank 30.

[0050] A pressure control valve 50 may be provided between the first gas-liquid separation tank 20c and the second gas-liquid separation tank 30 to control the pressure of the second gas-liquid separation tank 30 to be lower than the pressure of the first gas-liquid separation tank 20c. Furthermore, with dotted line L in FIG. 2 as the boundary, the pressure in the gas flow path is controlled to be lower on the right side of dotted line L than on the left side. Therefore, in the second gas-liquid separation tank 30, lower olefins dissolved in water can be released and separated by utilizing the pressure difference with the pressurized first gas-liquid separation tank 20c. Thus, a pressure control valve 50 may be provided between the first gas-liquid separation tank 20c included in the olefin production apparatus 80c, which is the final stage and located most downstream among the multiple olefin production apparatuses 80a, 80b, and 80c, and the second gas-liquid separation tank 30. When the number of stages in the olefin production apparatus is n, a pressure control valve 50 may be provided between the first gas-liquid separation tank of the n-th olefin production apparatus, which is the final stage and located most downstream, and the second gas-liquid separation tank 30. That is, a pressure control valve 50 may be provided to control the pressure of the second gas-liquid separation tank 30 to be lower than the pressure of the first gas-liquid separation tank 20 of the olefin production apparatus, which is the final stage.

[0051] On the other hand, the hydrocarbons containing lower olefins and the liquid containing water separated in the first gas-liquid separation tanks 20a, 20b, and 20c are transferred to the second gas-liquid separation tank 30 via a flow path separate from that for the gas containing lower olefins, and are collected.

[0052] First flow control valves 60a, 60b, 60c may be provided in the liquid flow paths connecting the first gas-liquid separation tanks 20a, 20b, 20c and the second gas-liquid separation tank 30, respectively. The first flow control valves 60a, 60b, 60c enable management so that a constant amount of liquid is always maintained in the first gas-liquid separation tanks 20a, 20b, 20c and the second gas-liquid separation tank 30. This makes it easier to control the pressure of the second gas-liquid separation tank 30 to be lower than the pressure of the first gas-liquid separation tank 20c.

[0053] The lower olefins released from the liquid in the second gas-liquid separation tank 30 are combined with the gas containing lower olefins transferred from the first gas-liquid separation tank 20c to the second gas-liquid separation tank 30 and are recovered through the flow path 70. Meanwhile, the liquid from which the lower olefins have been released in the second gas-liquid separation tank 30 is released from the second gas-liquid separation tank 30 by the second flow control valve 61, and the amount of liquid in the second gas-liquid separation tank 30 is adjusted.

[0054] In this way, the yield of light olefins can be improved by producing gas containing light olefins in three stages, namely, reactors 10a, 10b, and 10c, and then separating and recovering it in four stages, namely, first gas-liquid separation tanks 20a, 20b, and 20c, and second gas-liquid separation tank 30. By applying this method to a process provided with multiple stages of reactors and a first gas-liquid separation tank, it is possible to construct a production system that reduces raw materials containing unreacted carbon dioxide and / or carbon monoxide and hydrogen, and improves the yield of light olefins.

[0055] As described above, the olefin production system 1a according to this embodiment includes reactors 10a, 10b, 10c, coolers 40a, 40b, 40c, and first gas-liquid separation tanks 20a, 20b, 20c, and may include a plurality of olefin production apparatuses 80a, 80b, 80c connected in series. Furthermore, liquid transferred from two or more first gas-liquid separation tanks 20a, 20b, 20c included in the plurality of olefin production apparatuses 80a, 80b, 80c may be collected in the second gas-liquid separation tank 30 via first flow control valves 60a, 60b, 60c. Therefore, an olefin production system can be provided that improves the yield of lower olefins in a reaction using a raw material containing at least one of carbon dioxide and carbon monoxide.

[0056] Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other.

[0057] The present disclosure can contribute, for example, to Goal 13 of the United Nations-led Sustainable Development Goals (SDGs), "Take urgent action to combat climate change and its impacts."

[0058] The entire contents of Japanese Patent Application No. 2023-210223 (filing date: December 13, 2023) are incorporated herein by reference.

[0059] 1, 1a Olefin production system 10, 10a, 10b, 10c Reactor 20, 20a, 20b, 20c First gas-liquid separation tank 30 Second gas-liquid separation tank 40, 40a, 40b, 40c Cooler 50 Pressure control valve 80a, 80b, 80c Olefin production apparatus

Claims

1. An olefin production system comprising: a reactor for producing hydrocarbons containing lower olefins and water from a raw material containing at least one of carbon dioxide and carbon monoxide and hydrogen; a first gas-liquid separation tank for separating the product produced in the reactor into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water; and a second gas-liquid separation tank connected to the first gas-liquid separation tank for separating the gas containing lower olefins from the liquid transferred from the first gas-liquid separation tank, wherein the lower olefins include at least one selected from the group consisting of ethylene, propylene, butene and butadiene.

2. The olefin production system according to claim 1, further comprising a cooler for cooling the product produced in the reactor, and the first gas-liquid separation tank separates the product cooled in the cooler into the gas and the liquid.

3. An olefin production system according to claim 1 or 2, wherein the pressure of the second gas-liquid separation tank is lower than the pressure of the first gas-liquid separation tank.

4. An olefin production system according to any one of claims 1 to 3, comprising a pressure control valve installed between the first gas-liquid separation tank and the second gas-liquid separation tank, for controlling the pressure of the second gas-liquid separation tank to be lower than the pressure of the first gas-liquid separation tank.

5. An olefin production system according to any one of claims 1 to 4, wherein the second gas-liquid separation tank can be heated.

6. The olefin production system according to claim 2, comprising a plurality of olefin production apparatuses connected in series, each including the reactor, the cooler and the first gas-liquid separation tank, wherein liquid transferred from two or more of the plurality of first gas-liquid separation tanks included in the plurality of olefin production apparatuses is collected in a second gas-liquid separation tank.

7. A method for producing olefins, comprising: an olefin production step of producing hydrocarbons containing lower olefins and water from a raw material containing at least one of carbon dioxide and carbon monoxide and hydrogen in a reactor; a gas-liquid separation step of cooling the product obtained in the olefin production step in a cooler and then separating the product into a gas containing lower olefins and a liquid containing hydrocarbons containing lower olefins and water in a first gas-liquid separation tank; a transfer step of transferring the gas and the liquid obtained in the gas-liquid separation step to a second gas-liquid separation tank; and an olefin separation step of separating lower olefins from the liquid transferred to the second gas-liquid separation tank in the transfer step.

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