Olefin production method and implementation step

Abstract

The present invention provides an olefin production method comprising: a thermal decomposition step for thermally decomposing a waste plastic feedstock to obtain a hydrocarbon stream; a crude olefin generation step for supplying the hydrocarbon stream, along with kerosene / gas oil and / or heavy oil, to a catalytic cracking device to obtain crude olefins; a separation step for separating C2-4 olefins from the crude olefins; and a catalyst regeneration step for using a catalyst regeneration device to regenerate the catalyst used in the crude olefin generation step and returning the regenerated catalyst to the catalytic cracking device, wherein at least one of the temperature of the catalytic cracking device and the amounts of the kerosene / gas oil and / or the heavy oil supplied to the catalytic cracking device is controlled on the basis of the measurement values of the flow rates of ethylene and propylene in the crude olefins in the crude olefin generation step.

Description

Method and Implementation Process for Producing Olefins

[0001] The present invention relates to a method and implementation process for producing olefins.

[0002] Plastic products are produced using petrochemical products obtained, for example, by a method of decomposing hydrocarbons derived from crude oil as raw materials. There are many such decomposition methods, and examples of decomposition methods using a catalyst include fluid catalytic cracking. In fluid catalytic cracking, hydrocarbon oil is subjected to catalytic cracking using a catalyst containing zeolite or the like, and separation and purification are performed to obtain petrochemical products, fuel oil, and the like.

[0003] Since petrochemical products are used for various applications, various process conditions for catalytic cracking have been studied in order to obtain desired petrochemical products. For example, Patent Document 1 proposes using a specific catalyst containing zeolite to obtain a desired petrochemical product in catalytic cracking.

[0004] Japanese Unexamined Patent Application Publication No. 2006-305490

[0005] Meanwhile, from the viewpoint of recycling resources, the regeneration and reuse of plastics have attracted attention. For example, processes such as reuse, material recycling, and chemical recycling are performed to recycle waste plastics. In particular, chemical recycling can chemically decompose plastics and regenerate them into petrochemical raw materials, so it has the potential to overcome the limit of performance degradation caused by recycling.

[0006] However, when catalytic cracking is performed using a hydrocarbon stream obtained by pyrolyzing a waste plastic raw material, the composition of the obtained catalytic cracked product varies from production to production because the composition of the waste plastic raw material varies from production to production. From the viewpoint of chemical recycling, in order to regenerate plastics, it is required that the flow rate or proportion of ethylene and propylene in the olefin obtained by catalytic cracking falls within a specific range. However, when catalytic cracking is performed using a waste plastic raw material, there is a problem that it is difficult to make the flow rate or proportion of ethylene and propylene in the obtained olefin fall within a specific range.

[0007] In view of the above-mentioned problems, the object of the present invention is to provide a method for producing olefins and a process for implementing them that allows control of the flow rate or ratio of ethylene and propylene obtained by catalytic cracking, even when using waste plastic raw materials.

[0008] The present invention provides a method for producing olefins, comprising: a thermal decomposition step of thermally decomposing a waste plastic raw material containing polyolefin to obtain a hydrocarbon flow; a crude olefin production step of supplying the hydrocarbon flow and kerosene and / or heavy oil to a catalytic cracking apparatus that decomposes hydrocarbons by contacting a catalyst containing zeolite with hydrocarbons to obtain crude olefins; a separation step of separating olefins having 2 to 4 carbon atoms from the crude olefins; and a catalyst regeneration step of regenerating the catalyst used in the crude olefin production step using a catalyst regeneration apparatus that regenerates the catalyst by heating, and returning the regenerated catalyst to the catalytic cracking apparatus, wherein in the crude olefin production step, the flow rates of ethylene and propylene in the crude olefins are measured, and at least one of the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus is controlled based on the measured values.

[0009] An implementation step according to the present invention is an implementation step for carrying out the method for producing the olefin, and includes the thermal decomposition step.

[0010] An implementation step according to the present invention is an implementation step for carrying out the method for producing the olefin, and includes the crude olefin production step and the catalyst regeneration step.

[0011] An implementation step according to the present invention is an implementation step for carrying out the method for producing the olefin, and includes the crude olefin production step, the catalyst regeneration step, and the hot air generation step.

[0012] An implementation step according to the present invention is an implementation step for carrying out the method for producing the olefin, and includes the separation step.

[0013] According to the present invention, it is possible to provide a method for producing olefins and a process for carrying them out, which allows for control over the flow rate or ratio of ethylene and propylene obtained by catalytic cracking, even when using waste plastic raw materials.

[0014] The following describes a method for producing olefins according to embodiments of the present invention. The present invention is not limited to the following embodiments.

[0015] The method for producing olefins according to this embodiment includes: a thermal decomposition step of obtaining a hydrocarbon flow by thermal decomposing a waste plastic raw material containing polyolefins; a crude olefin production step of obtaining crude olefins by supplying the hydrocarbon flow and kerosene and / or heavy oil to a catalytic cracking apparatus that decomposes hydrocarbons by contacting a catalyst containing zeolite with hydrocarbons; a separation step of separating olefins having 2 to 4 carbon atoms from the crude olefins; and a catalyst regeneration step of regenerating the catalyst used in the crude olefin production step using a catalyst regeneration apparatus that regenerates the catalyst by heating, and returning the regenerated catalyst to the catalytic cracking apparatus.

[0016] First, the olefin manufacturing apparatus used in the olefin manufacturing method according to this embodiment will be described. The olefin manufacturing apparatus used in this embodiment includes: a pyrolysis apparatus that obtains a hydrocarbon flow by pyrolysis of waste plastic raw materials containing polyolefins; a catalytic cracking apparatus that receives the hydrocarbon flow and kerosene and / or heavy oil, and contacts a catalyst containing zeolite with hydrocarbons contained in the hydrocarbon flow and the kerosene and / or heavy oil to decompose hydrocarbons and obtain crude olefins; a separation apparatus that separates olefins having 2 to 4 carbon atoms from the crude olefins; and a catalyst regeneration apparatus that regenerates the zeolite-containing catalyst used in the catalytic cracking apparatus by heating and returns the regenerated catalyst to the catalytic cracking apparatus.

[0017] The olefin manufacturing apparatus may further include a hot air generator that generates hot air containing oxygen gas.

[0018] [Pyrolysis Apparatus] The pyrolysis apparatus is a device that obtains a hydrocarbon flow by pyrolysis of waste plastic raw materials containing polyolefins. More specifically, the pyrolysis apparatus is a device that pyrolysiss waste plastic raw materials containing polyolefins to obtain pyrolysis products and obtains a hydrocarbon flow from the pyrolysis products. The pyrolysis apparatus has a reaction vessel for pyrolysis of the waste plastic raw materials. The hydrocarbon flow obtained from the pyrolysis apparatus is supplied to a catalytic cracking apparatus, which will be described later.

[0019] Examples of the pyrolysis apparatus include a stirred-tank pyrolysis apparatus, a rotary pyrolysis apparatus, an internal circulating fluidized bed apparatus, and an external circulating fluidized bed apparatus. The stirred-tank pyrolysis apparatus is an apparatus that pyrolysis waste plastic supplied to a reaction vessel by heating it from the outside while stirring it with a stirrer inside the reaction vessel. The rotary pyrolysis apparatus is an apparatus that pyrolysis waste plastic supplied to a reaction vessel while rotating it. The internal circulating fluidized bed apparatus and the external circulating fluidized bed apparatus are apparatuses that can promote pyrolysis by using a fluidized bed formed of fluidized solid particles. The pyrolysis apparatus may be used individually, or two or more types may be combined and connected in parallel or in series. When two or more types of pyrolysis apparatus are combined and connected in parallel, the pyrolysis apparatus may be used with all pyrolysis apparatuses operating simultaneously, or with some of the pyrolysis apparatuses stopped. The pyrolysis apparatus is preferably at least one selected from the group consisting of a stirred-tank pyrolysis apparatus, a rotary pyrolysis apparatus, an internal circulating fluidized bed apparatus, and an external circulating fluidized bed apparatus.

[0020] The internal pressure of the pyrolysis apparatus is preferably between atmospheric pressure - 50 kPaG and atmospheric pressure + 50 kPaG.

[0021] The pyrolysis apparatus may have at least one of a refluxing device and a condenser. The refluxing device and the condenser liquefy at least a portion of the pyrolysis product. The pyrolysis apparatus may have piping connecting the reaction vessel to at least one of the refluxing device and the condenser in order to supply at least a portion of the liquefied pyrolysis product back to the reaction vessel. The pyrolysis apparatus may have multiple refluxing devices and multiple condensers.

[0022] The pyrolysis apparatus may heat the waste plastic raw material using any heat source. Examples of the heat source include heat from burning fuel, heat generated by an electric heater, and heat generated during exhaust gas treatment. Examples of the fuel include gaseous pyrolysis products contained in the pyrolysis product, and natural gas. The pyrolysis apparatus may use one of the heat sources alone, or it may use two or more of the heat sources in combination.

[0023] [Catalytic Cracking Apparatus] The catalytic cracking apparatus is supplied with the hydrocarbon flow and light oil and / or heavy oil described later, and is used to crack hydrocarbons by contacting a catalyst containing zeolite with the hydrocarbon flow and the hydrocarbons contained in the light oil and / or heavy oil, thereby obtaining crude olefins described later. The hydrocarbons are those contained in the hydrocarbon flow obtained in the pyrolysis apparatus and the light oil and / or heavy oil. The crude olefins obtained in the catalytic cracking apparatus are supplied to a separation apparatus described later.

[0024] The catalytic cracking apparatus has a measuring unit for measuring the flow rates of ethylene and propylene in the crude olefin.

[0025] The catalytic cracking apparatus has a first control unit that controls the temperature of the catalytic cracking apparatus based on the measurement value obtained by the measurement unit. The catalytic cracking apparatus has a second control unit that controls the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus based on the measurement value obtained by the measurement unit. The catalytic cracking apparatus may also have a third control unit that controls the amount of fuel oil and fuel gas supplied to a hot air generator, which will be described later, based on the measurement value obtained by the measurement unit.

[0026] Examples of the catalytic cracking apparatus include a fluidized bed catalytic cracking apparatus, a moving bed catalytic cracking apparatus, and a stationary bed catalytic cracking apparatus. The fluidized bed catalytic cracking apparatus is an apparatus that decomposes hydrocarbons by contacting hydrocarbons with a fluidized particulate catalyst. The moving bed catalytic cracking apparatus is an apparatus that decomposes hydrocarbons by contacting hydrocarbons with a granular catalyst as it moves from top to bottom within the apparatus. The catalytic cracking apparatus may be used individually, or two or more may be combined and connected in parallel or in series. The catalytic cracking apparatus is preferably at least one of a fluidized bed catalytic cracking apparatus and a moving bed catalytic cracking apparatus, and more preferably a fluidized bed catalytic cracking apparatus.

[0027] [Separation device] The separation device is a device for separating olefins having 2 to 4 carbon atoms from crude olefins. The separation device may also be a device for further separating fuel oil and fuel gas from crude olefins. That is, the separation device may be a device for separating olefins having 2 to 4 carbon atoms, fuel oil, and fuel gas from crude olefins. The olefins having 2 to 4 carbon atoms obtained in the separation device may be used as various petrochemical raw materials. The fuel oil and fuel gas obtained in the separation device may be supplied to a hot air generator described later and used as fuel.

[0028] Examples of the separation apparatus include distillation apparatus, gas-liquid separator, adsorption separator, membrane separator, and washing apparatus. The separation apparatus may be used individually, or two or more may be combined and connected in parallel or in series. When the separation apparatus is used individually, the separation apparatus is preferably a distillation apparatus. When multiple separation apparatuses are used, the multiple separation apparatuses are preferably at least two selected from the group consisting of distillation apparatus, gas-liquid separator, adsorption separator, membrane separator, and washing apparatus.

[0029] [Hot air generator] The hot air generator is a device that generates hot air containing oxygen gas. The hot air generated by the hot air generator may be supplied to a catalyst regeneration device described later and used as a heat source for regenerating the catalyst.

[0030] Examples of the hot air generating devices include direct combustion type hot air generating devices and indirect heating type hot air generating devices. The direct combustion type hot air generating device is a device that uses combustion gas generated by burning fuel and air heated by the combustion gas to produce hot air. The indirect heating type hot air generating device is a device that generates hot air by heating air supplied to the inside of the device with an external heat source via a heat exchanger. As the heat source, for example, heat from burning fuel, heat generated by an electric heater, steam, etc., can be used. The hot air generating devices may be used individually, or two or more may be combined and connected in parallel or in series. The hot air generating device is preferably the direct combustion type hot air generating device.

[0031] The hot air generator may be supplied with oxygen gas from an external source, or it may be supplied with air whose oxygen concentration has been increased by an oxygen enrichment device.

[0032] [Catalyst Regeneration Device] The catalyst regeneration device is a device that regenerates the catalyst containing zeolite used in the catalytic cracking device by heating, and returns the regenerated catalyst to the catalytic cracking device. The catalyst regeneration device may also be a device to which hot air generated by the hot air generator is supplied, and which regenerates the catalyst containing zeolite used in the catalytic cracking device by heating with the hot air as the heat source, and returns the regenerated catalyst to the catalytic cracking device. The catalyst regenerated in the catalyst regeneration device is the catalyst used in the catalytic cracking device. The catalyst regenerated in the catalyst regeneration device is supplied again to the catalytic cracking device.

[0033] Examples of the catalyst regeneration apparatus include a fluidized bed catalyst regeneration apparatus, a mobile bed catalyst regeneration apparatus, and a stationary bed catalyst regeneration apparatus. The fluidized bed catalyst regeneration apparatus is an apparatus that regenerates a catalyst by heating it when fluidized particulate catalyst comes into contact with air. The mobile bed catalyst regeneration apparatus is an apparatus that regenerates a catalyst by heating it as granular catalyst moves from top to bottom inside the apparatus. The catalyst regeneration apparatus may be used individually, or two or more may be combined and connected in parallel or in series. The catalyst regeneration apparatus is preferably at least one of a fluidized bed catalyst regeneration apparatus and a mobile bed catalyst regeneration apparatus, and more preferably a fluidized bed catalyst regeneration apparatus.

[0034] An example of the catalyst regeneration device is a hot air supply type catalyst regeneration device. In the hot air supply type catalyst regeneration device, the catalyst is heated by supplying hot air containing oxygen gas to promote combustion.

[0035] Next, a method for producing olefins according to this embodiment will be described. The method for producing olefins according to this embodiment includes a thermal decomposition step, a crude olefin production step, a separation step, and a catalyst regeneration step. The method for producing olefins according to this embodiment may further include a hot air generation step.

[0036] (Thermal Decomposition Process) The thermal decomposition process is a process of thermally decomposing a waste plastic raw material containing polyolefin to obtain a hydrocarbon flow. More specifically, the thermal decomposition process is a process of thermally decomposing a waste plastic raw material containing polyolefin to obtain a thermal decomposition product, and obtaining a hydrocarbon flow from the thermal decomposition product. The thermal decomposition process includes a reaction that reduces the molecular weight of the polymer components contained in the waste plastic raw material and converts them into hydrocarbons. That is, the hydrocarbon flow obtained in the thermal decomposition process contains hydrocarbons. In the thermal decomposition process, thermal decomposition residue may be generated from the waste plastic raw material.

[0037] The pyrolysis step can be carried out using the pyrolysis apparatus described above. Preferably, the pyrolysis step can be carried out using at least one selected from the group consisting of a stirred-tank pyrolysis apparatus, a rotary pyrolysis apparatus, an internal circulating fluidized bed apparatus, and an external circulating fluidized bed apparatus.

[0038] The term "waste plastic raw material" refers to plastic products that have been used for some end use.

[0039] Examples of the polyolefin contained in the waste plastic raw material include olefin-based polymers containing monomer units derived from α-olefin. The olefin-based polymer may be an olefin homopolymer, or may be a copolymer containing monomer units derived from olefin. The waste plastic raw material may contain at least one of an olefin homopolymer and a copolymer containing monomer units derived from olefin as the olefin-based polymer.

[0040] Examples of the monomer derived from olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, and the like.

[0041] The copolymer containing monomer units derived from olefin may be a copolymer containing monomer units derived from two or more different olefins, or may be a copolymer containing monomer units derived from olefin and monomer units other than monomer units derived from olefin. The waste plastic raw material may contain one or two or more kinds of copolymers containing monomer units derived from olefin as the olefin-based polymer.

[0042] Examples of monomers other than monomer units derived from olefin include alkylene oxides such as ethylene oxide, and esters such as ethylene terephthalate. The monomer other than monomer units derived from olefin may be alkylene oxide or ethylene terephthalate.

[0043] Examples of copolymers containing monomer units derived from olefins include propylene copolymers containing monomer units derived from propylene. Examples of said propylene copolymers include propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-1-hexene copolymers, propylene-1-octene copolymers, propylene-ethylene-1-butene copolymers, propylene-ethylene-1-hexene copolymers, and propylene-ethylene-1-octene copolymers. Said propylene copolymer may be a random copolymer or may be a heterophasic propylene polymer material.

[0044] Said waste plastic raw material may contain polymer components other than the polyolefin. Examples of polymer components other than said polyolefin include chlorinated polyethylene, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyethylene terephthalate (PET), polybutylene terephthalate, polystyrene, nylon 66, and the like.

[0045] From the viewpoint of increasing the content of polyolefin contained in said waste plastic raw material, said waste plastic raw material may be pretreated before being supplied to said pyrolysis apparatus. Examples of said pretreatment include sorting treatment, crushing treatment, washing treatment, drying treatment, melting treatment, dechlorination treatment, and the like. Said sorting treatment is a treatment of sorting plastics containing polyolefin from said waste plastic raw material. Said crushing treatment is a treatment of crushing the sorted plastics. Said washing treatment is a treatment of washing the crushed plastics. Said drying treatment is a treatment of drying the washed plastics. Said melting treatment is a treatment of heating plastics to turn them into a liquid state. Said dechlorination treatment is a treatment of removing chlorine contained in plastics.

[0046] The content of said polyolefin in said pretreated said waste plastic raw material, relative to 100% by mass of the waste plastic raw material, is preferably 80% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more.

[0047] The hydrocarbon stream according to this embodiment contains hydrocarbons. The hydrocarbon stream may also contain oxygen-containing compounds, nitrogen-containing compounds, sulfur-containing compounds, or chlorine-containing compounds.

[0048] The hydrocarbons contained in the hydrocarbon stream may include light hydrocarbons having fewer than 20 carbon atoms and heavy hydrocarbons having 20 or more carbon atoms. Examples of the light hydrocarbons include alkanes such as methane, ethane, and propane; olefins such as ethylene, propylene, and butene; diolefins such as butadiene; aromatic hydrocarbons such as benzene, toluene, and xylene; and cycloalkanes such as cyclohexane. From the viewpoint of improving the yield of olefins in the method for producing olefins, the hydrocarbon stream preferably contains the olefins as the light hydrocarbons.

[0049] Examples of the oxygen-containing compounds include organic compounds having oxygen functional groups such as carboxyl groups, hydroxyl groups, and ether groups, as well as carbon dioxide and carbon monoxide. Examples of the nitrogen-containing compounds include organic compounds having nitrogen functional groups such as amino groups and isocyanate groups, nitrogen ring compounds, nitric oxide, and nitrogen dioxide. Examples of the sulfur-containing compounds include organic compounds having sulfur functional groups such as thiol groups, thioether groups, and sulfonyl groups, sulfur ring compounds, and hydrogen sulfide. Examples of the chlorine-containing compounds include methyl chloride, chlorine-containing alkanes such as chloroform, and chlorine-containing aromatic compounds.

[0050] In the pyrolysis step, the hydrocarbon stream may be vaporized or liquefied. Preferably, in the pyrolysis step, the hydrocarbon stream is liquefied. In this specification, the liquefied hydrocarbon stream may be referred to as hydrocarbon oil. Since the hydrocarbon stream is liquefied in the pyrolysis step, it is easy to transport the hydrocarbon stream, and therefore the pyrolysis step and the steps downstream therefrom can be carried out in different locations. That is, in the method for producing olefins according to this embodiment, the pyrolysis step and the steps downstream therefrom may be carried out intermittently.

[0051] In the pyrolysis step, at least a portion of the pyrolysis product may be liquefied. At least a portion of the liquefied pyrolysis product may be supplied back to the pyrolysis apparatus.

[0052] The heat source in the pyrolysis step may be heat generated by burning fuel, heat generated by an electric heater, or heat generated during exhaust gas treatment. Examples of the fuel include gaseous pyrolysis products contained in the pyrolysis product, and natural gas. The pyrolysis step may be carried out with one heat source alone, or with a combination of two or more heat sources.

[0053] In the aforementioned thermal decomposition step, the virgin plastic raw material containing polyolefin may be further thermally decomposed. The virgin plastic raw material means a polymer produced by a process including a polymerization step, a resin composition containing said polymer, or a plastic product using said polymer or resin composition that has not been used for any end use. The polyolefin contained in the virgin plastic raw material is the same as the polyolefin contained in the waste plastic raw material.

[0054] In the aforementioned pyrolysis step, the temperature at which pyrolysis is carried out is preferably 350°C to 800°C, more preferably 370°C to 600°C, and even more preferably 380°C to 550°C.

[0055] The yield of hydrocarbon flow is improved when the temperature of the pyrolysis process is within the above numerical range.

[0056] In the aforementioned pyrolysis step, the pressure at which the pyrolysis is carried out is preferably between atmospheric pressure - 50 kPaG and atmospheric pressure + 50 kPaG.

[0057] The thermal decomposition is accelerated when the pressure in the thermal decomposition process is within the above numerical range.

[0058] (Crude Olefin Production Process) The crude olefin production process is a process of obtaining crude olefins by supplying the hydrocarbon stream and light oil and / or heavy oil to a catalytic cracking apparatus that decomposes hydrocarbons (also called catalytic cracking) by contacting a catalyst containing zeolite with hydrocarbons. The catalytic cracking includes a reaction that breaks the carbon-carbon single bond contained in one molecule of hydrocarbon and produces two molecules of olefin having a carbon-carbon double bond. That is, the crude olefin includes olefins produced by the catalytic cracking of hydrocarbons contained in the hydrocarbon stream and hydrocarbons contained in the light oil and / or heavy oil. In the crude olefin production process, the hydrocarbon stream obtained in the thermal decomposition process and the light oil and / or heavy oil are supplied to the catalytic cracking apparatus.

[0059] The crude olefin production step can be carried out using the catalytic cracking apparatus described above. The crude olefin production step can preferably be carried out using at least one of a fluidized bed catalytic cracking apparatus and a moving bed catalytic cracking apparatus, and more preferably using a fluidized bed catalytic cracking apparatus.

[0060] The hydrocarbons and hydrocarbon streams in the crude olefin production step are the same as those described in the section on the pyrolysis step.

[0061] In this specification, "kerosene oil" means a petroleum component containing at least one of kerosene or light oil. That is, in the crude olefin production step, the hydrocarbon flow and kerosene may be supplied to the catalytic cracking unit, the hydrocarbon flow and light oil may be supplied, the hydrocarbon flow and heavy oil may be supplied, the hydrocarbon flow and kerosene and light oil may be supplied, the hydrocarbon flow and kerosene and heavy oil may be supplied, the hydrocarbon flow and light oil and heavy oil may be supplied, or the hydrocarbon flow and kerosene, light oil and heavy oil may be supplied.

[0062] Examples of hydrocarbons contained in the aforementioned kerosene include hydrocarbons having 10 to 20 carbon atoms, cycloalkane derivatives having less than 10 carbon atoms, and aromatic hydrocarbons. Examples of hydrocarbons having 10 to 20 carbon atoms include decane, undecane, dodecane, and hexadecane. Examples of cycloalkane derivatives having less than 10 carbon atoms include methylcyclopentane, dimethylcyclopentane, and methylcyclohexane. Examples of aromatic hydrocarbons include toluene, xylene, and naphthalene.

[0063] The kerosene contains hydrocarbons. Examples of hydrocarbons contained in the kerosene include hydrocarbons having 10 to 15 carbon atoms, cycloalkane derivatives having less than 10 carbon atoms, and aromatic hydrocarbons. Examples of hydrocarbons having 10 to 15 carbon atoms include decane, undecane, dodecane, and tetradecane. The cycloalkane derivatives and aromatic hydrocarbons having less than 10 carbon atoms are the same as those contained in the kerosene.

[0064] The diesel fuel contains hydrocarbons. Examples of hydrocarbons contained in the diesel fuel include hydrocarbons having 10 to 20 carbon atoms, cycloalkane derivatives having less than 10 carbon atoms, and aromatic hydrocarbons. The hydrocarbons having 10 to 20 carbon atoms, cycloalkane derivatives having less than 10 carbon atoms, and aromatic hydrocarbons are the same as those contained in the kerosene diesel fuel.

[0065] The heavy oil contains hydrocarbons. Examples of hydrocarbons contained in the heavy oil include hydrocarbons having 21 or more carbon atoms, cycloalkane derivatives, and aromatic hydrocarbons. Examples of hydrocarbons having 21 or more carbon atoms include pentacosane and triacontane. Examples of cycloalkane derivatives include decahydronaphthalene. Examples of aromatic hydrocarbons include dimethylanthracene.

[0066] The flash point of the light oil may be 40°C or higher and 100°C or lower, or 45°C or higher and 80°C or lower.

[0067] The flash point of the kerosene may be 40°C or higher and 60°C or lower, or 45°C or higher and 55°C or lower.

[0068] The flash point of the light oil may be 45°C or higher and 100°C or lower, or 50°C or higher and 80°C or lower.

[0069] The flash point of the heavy oil may be 60°C or higher and less than 150°C, or 70°C or higher and less than 120°C.

[0070] The flash points of the aforementioned kerosene, kerosene, light oil, and heavy oil can be measured by Method A as specified in JIS K2265-3.

[0071] In the crude olefin production step, the flow rates of ethylene and propylene in the crude olefin are measured, and based on these measurements, at least one of the following is controlled: the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus.

[0072] In this specification, “based on the measured values” means either converting the flow rates of ethylene and propylene in the crude olefin to the ratio of propylene to ethylene in the crude olefin and basing the results on that ratio, or converting the flow rates of ethylene and propylene in the crude olefin to the yield of ethylene and propylene in the crude olefin and basing the results on that yield.

[0073] In the crude olefin production step, the flow rates of ethylene and propylene in the crude olefin are measured, and the resulting flow rates of ethylene and propylene are converted to the ratio of propylene to ethylene in the crude olefin. Based on this ratio, the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus may be controlled. In the crude olefin production step, the flow rates of ethylene and propylene in the crude olefin are measured, and the resulting flow rates of ethylene and propylene are converted to the yield of ethylene and propylene in the crude olefin. Based on this yield, the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus may be controlled.

[0074] In the crude olefin production step, the temperature of the catalytic cracking apparatus may be 400°C or more and 800°C or less, 450°C or more and 650°C or less, or 500°C or more and 600°C or less.

[0075] The temperature of the catalytic decomposition apparatus is the temperature inside the catalytic decomposition apparatus. That is, the temperature of the catalytic decomposition apparatus is a measurement value obtained using a thermometer or thermocouple placed inside the catalytic decomposition apparatus.

[0076] The temperature of the catalytic cracking apparatus may be controlled by the surface temperature of the catalyst regenerated in the catalyst regeneration process described later. The surface temperature of the catalyst regenerated in the catalyst regeneration process may be controlled by the temperature at which the catalyst regeneration process is carried out. In other words, the temperature of the catalytic cracking apparatus may be controlled by the temperature at which the catalyst regeneration process is carried out.

[0077] If the method for producing olefins according to this embodiment includes a hot air generation step described later, the temperature at which the catalyst regeneration step is carried out may be controlled by the temperature of the hot air generated in the hot air generation step described later. The temperature of the hot air may be controlled by the amount of fuel oil and fuel gas supplied as fuel to the hot air generator. That is, the temperature of the catalytic cracking apparatus may be controlled based on the amount of fuel.

[0078] In the crude olefin production step, the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus may be 0.05 times or more and 20 times or less, or 0.1 times or more and 10 times or less, relative to the amount of hydrocarbon flow supplied to the catalytic cracking apparatus.

[0079] The control of the temperature of the catalytic cracking apparatus is not limited to a specific range of temperature increase or decrease. The temperature of the catalytic cracking apparatus is adjusted as appropriate to achieve a desired ratio of propylene to ethylene in the crude olefin, and the yield of ethylene and propylene in the crude olefin. For example, increasing the temperature of the catalytic cracking apparatus can lower the ratio of propylene to ethylene in the crude olefin and increase the yield of ethylene and propylene in the crude olefin.

[0080] The control of the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus is not limited to any specific means of increasing or decreasing the amount supplied. The amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus is adjusted as appropriate to achieve the desired ratio of propylene to ethylene in the crude olefin, and the yield of ethylene and propylene in the crude olefin.

[0081] Examples of catalysts containing zeolite include those containing beta-type zeolite, faujasite-type zeolite, L-type zeolite, ferrielite-type zeolite, mordenite-type zeolite, and MFI-type zeolite. Preferably, the zeolite-containing catalyst is one containing MFI-type zeolite. The catalyst containing MFI-type zeolite has an MFI structure.

[0082] The catalyst containing zeolite is preferably an H-type zeolite having hydrogen cations as acid sites.

[0083] A catalyst containing zeolite preferably further comprises at least one of silica and alumina. The catalyst containing zeolite may further contain at least one atom selected from the group consisting of titanium, chromium, manganese, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, iridium, platinum, boron, nitrogen, sodium, potassium, magnesium, phosphorus, zinc, and gallium atoms.

[0084] The average particle size of the catalyst containing zeolite may be 50 μm or more and 120 μm or less, or 60 μm or more and 90 μm or less.

[0085] The average particle size of a zeolite-containing catalyst is determined based on volume-based particle size distribution measurement data obtained by laser diffraction according to the method specified in JIS R1629. In this particle size distribution measurement data, it refers to the particle size at which the cumulative total from the smallest particle size reaches 50% (also called the 50% equivalent particle size). This defined particle size is generally called the "50% equivalent particle size" and is sometimes denoted as "D50".

[0086] By having the average particle size of the catalyst containing zeolite within the above numerical range, the ratio of unreacted hydrocarbon flow to kerosene and / or heavy oil can be reduced in the crude olefin production step.

[0087] In the crude olefin production step, a fluidized bed, a mobile bed, or a stationary bed may be formed using a catalyst containing zeolite. Preferably, in the crude olefin production step, a fluidized bed is formed using a catalyst containing zeolite.

[0088] In the crude olefin production step, some of the hydrocarbons undergo polycondensation to form carbides (also called coke), and this coke may adhere to the catalyst surface. In one embodiment, the catalyst used in the crude olefin production step may be a catalyst on which the coke has adhered to the catalyst surface (also called a coke-containing catalyst).

[0089] In the crude olefin production step, the weight space velocity (WHSV) required for the catalytic decomposition of the catalyst containing zeolite is preferably 0.5 h. －１ More than 30 hours －１ The following, more preferably 1h －１ 15 hours －１ The following applies:

[0090] By having the weight space velocity (WHSV) required for catalytic cracking of the zeolite-containing catalyst in the crude olefin production step be within the above numerical range, the proportion of unreacted hydrocarbon flow to kerosene and / or heavy oil can be reduced in the crude olefin production step.

[0091] The crude olefin comprises an olefin, preferably an olefin, fuel oil, and fuel gas.

[0092] Examples of olefins included in the crude olefin include olefins having 2 to 4 carbon atoms. Examples of olefins having 2 to 4 carbon atoms include ethylene, propylene, 1-butene, 2-butene, and isobutene. The crude olefin according to this embodiment includes ethylene and propylene as olefins having 2 to 4 carbon atoms.

[0093] The fuel oil contained in the crude olefin preferably includes at least a portion of light oil and heavy oil.

[0094] The fuel gas contained in the crude olefin preferably contains an alkane having 1 to 4 carbon atoms. Examples of alkanes having 1 to 4 carbon atoms include methane, ethane, propane, and butane.

[0095] The olefin content in the crude olefin is preferably 50% by mass or more and 85% by mass or less, and more preferably 55% by mass or more and 80% by mass or less. From the viewpoint of improving the yield of olefins in the method for producing olefins, the content of olefins having 2 to 4 carbon atoms in the crude olefin is preferably 45% by mass or more and 80% by mass or less, and more preferably 50% by mass or more and 75% by mass or less.

[0096] The fuel oil content in the crude olefin may be 2% by mass or more and 15% by mass or 3% by mass or more and 10% by mass or less.

[0097] The content of the fuel gas in the crude olefin may be 2% by mass or more and 15% by mass or less, or 3% by mass or more and 10% by mass or less.

[0098] (Separation step) The separation step is a step of separating olefins having 2 to 4 carbon atoms from the crude olefin. Preferably, the separation step is a step of further separating the fuel oil and the fuel gas from the crude olefin. In the separation step, the crude olefin obtained in the crude olefin production step is supplied to the separation apparatus described above.

[0099] The crude olefin and olefins having 2 to 4 carbon atoms in the separation step, the fuel oil, and the fuel gas are the same as those described in the section on the crude olefin production step.

[0100] The separation step can be carried out using the separation apparatus described above. The separation step can be carried out using one or more of the separation apparatuses. When the separation step is carried out using one or more of the separation apparatuses, the separation step can preferably be carried out using a distillation apparatus. When the separation step is carried out using more of the separation apparatuses, the separation step can preferably be carried out using at least two types of separation apparatuses selected from the group consisting of a distillation apparatus, a gas-liquid separator, an adsorption separator, a membrane separator, and a washing apparatus.

[0101] (Hot air generation process) The hot air generation process is a process of generating hot air containing oxygen gas using a hot air generating device. The hot air generation process can be carried out using the hot air generating device described above. Preferably, the hot air generating device can be the direct combustion type hot air generating device.

[0102] The oxygen gas contained in the hot air may be the oxygen gas contained in the air supplied to the hot air generator, the oxygen gas contained in the air whose oxygen concentration has been increased by the oxygen enrichment device supplied to the hot air generator, or the oxygen gas supplied directly to the hot air generator.

[0103] The temperature of the hot air may be 300°C or more and 850°C or less, 400°C or more and 800°C or less, or 500°C or more and 750°C or less.

[0104] The temperature of the hot air is the temperature at the inlet of the catalyst regeneration device. That is, the temperature of the hot air is a measurement value obtained using a thermometer or thermocouple placed at the inlet of the catalyst regeneration device.

[0105] The hot air generation step may generate the hot air using fuel, or it may generate the hot air by burning the fuel. Examples of fuel include fuel oil and fuel gas. In the hot air generation step, the fuel oil and fuel gas obtained in the separation step may be supplied to the hot air generator. In the hot air generation step, preferably, at least a portion of the fuel oil and fuel gas is supplied to the hot air generator and used as fuel, and more preferably, at least a portion of the fuel oil and fuel gas is supplied to the hot air generator and burned and used as fuel.

[0106] In one embodiment of the olefin production method according to this embodiment, in the hot air generation step, at least a portion of the fuel oil and fuel gas is supplied to the hot air generator and used as fuel, and the temperature of the catalytic cracking apparatus is controlled based on the amount of fuel.

[0107] (Catalyst regeneration step) The catalyst regeneration step is a step of regenerating the catalyst used in the crude olefin production step using a catalyst regeneration device that regenerates the catalyst by heating, and returning the regenerated catalyst to the catalytic cracking device. In the catalyst regeneration step, the catalyst may be heated using hot air. That is, the catalyst regeneration step may be a step of supplying hot air to a catalyst regeneration device that regenerates the catalyst by heating, regenerating the catalyst used in the crude olefin production step with the hot air, and returning the regenerated catalyst to the catalytic cracking device. In the catalyst regeneration step, when the catalyst is heated using hot air, the hot air generated in the hot air generation step may be supplied to the catalyst regeneration device described above.

[0108] The hot air in the catalyst regeneration process is the same as that described in the section on the hot air generation process.

[0109] The catalyst regeneration step may be a step in which the catalyst is regenerated by burning off the coke adhering to the catalyst surface by heating, thereby removing the coke from the catalyst surface. In the catalyst regeneration step, preferably, the coke-containing catalyst generated in the crude olefin production step is supplied to the catalyst regeneration device.

[0110] In the catalyst regeneration step, the catalyst used in the crude olefin step may form a fluidized bed, a mobile bed, or a stationary bed. Preferably, in the catalyst regeneration step, the catalyst used in the crude olefin step is used to form a fluidized bed.

[0111] In one embodiment, in the crude olefin production step, a fluidized bed is formed by a catalyst containing zeolite, and in the catalyst regeneration step, a fluidized bed is formed by the catalyst used in the crude olefin production step. By forming a fluidized bed with the catalyst in the crude olefin production step and the catalyst regeneration step, the catalyst can reciprocate between the catalytic cracking apparatus and the catalyst regeneration apparatus.

[0112] In the catalyst regeneration step, the residence time for regenerating the catalyst used in the crude olefin step is preferably 60 seconds or more and 3600 seconds or less, and more preferably 120 seconds or more and 1800 seconds or less.

[0113] The residence time of the hot air required for catalyst regeneration in the catalyst regeneration apparatus is preferably 0.5 seconds or more and 5 seconds or less, and more preferably 1 second or more and 3 seconds or less.

[0114] The olefin production method according to this embodiment, when implemented in the manner described above, allows for control of the flow rate or ratio of ethylene and propylene obtained by catalytic cracking, even when using waste plastic raw materials.

[0115] The method for producing olefins according to this embodiment includes: a thermal decomposition step to obtain a hydrocarbon flow by thermal decomposing a waste plastic raw material containing polyolefin; a crude olefin production step to obtain crude olefins by supplying the hydrocarbon flow and light oil and / or heavy oil to a catalytic cracking apparatus that decomposes hydrocarbons by contacting a catalyst containing zeolite with hydrocarbons; a separation step to separate olefins having 2 to 4 carbon atoms from the crude olefins; and a catalyst regeneration step to regenerate the catalyst used in the crude olefin production step using a catalyst regeneration apparatus that regenerates the catalyst by heating, and return the regenerated catalyst to the catalytic cracking apparatus. In the crude olefin production step, the flow rates of ethylene and propylene in the crude olefins are measured, and at least one of the temperature of the catalytic cracking apparatus and the amount of light oil and / or heavy oil supplied to the catalytic cracking apparatus are controlled based on the measured values.

[0116] The olefin production method, with the above configuration, allows for the control of the flow rate or proportion of ethylene and propylene obtained by catalytic cracking by measuring the flow rates of ethylene and propylene in the crude olefin during the crude olefin production step, and controlling at least one of the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus based on the measured value.

[0117] The method for producing the olefin further includes a hot air generation step of generating hot air containing oxygen gas using a hot air generator, and in the catalyst regeneration step, the catalyst is heated using the hot air.

[0118] The olefin production method, with this configuration, suppresses localized heating of the catalyst in the catalyst regeneration step by heating the catalyst using the hot air generated in the hot air generation step, thereby suppressing a decrease in catalyst activity in the crude olefin production step. This allows for better control of the flow rate or ratio of ethylene and propylene obtained by catalytic cracking.

[0119] The method for producing the olefin is as follows: the separation step is a step of further separating fuel oil and fuel gas from the crude olefin; in the hot air generation step, at least a portion of the fuel oil and fuel gas is supplied to the hot air generator and used as fuel; and the temperature of the catalytic cracking apparatus is controlled based on the amount of fuel.

[0120] The olefin production method, with this configuration, allows for the temperature of the regenerated catalyst to be adjusted by adjusting the amount of fuel supplied to the hot air generator, thereby controlling the temperature of the catalytic cracking apparatus. This allows for further control of the flow rate or ratio of ethylene and propylene obtained by catalytic cracking.

[0121] Next, the implementation steps according to this embodiment will be described. Only the parts that differ from the embodiment for the olefin manufacturing method will be described.

[0122] The implementation steps according to this embodiment are steps for carrying out the above-described method for producing the olefin.

[0123] The implementation steps according to this embodiment include, in a first aspect, the thermal decomposition step. The thermal decomposition step is the same as that described in the embodiment relating to the method for producing olefins.

[0124] The implementation steps according to this embodiment include, in a second aspect, the crude olefin production step and the catalyst regeneration step. The crude olefin production step and the catalyst regeneration step are the same as those described in the embodiment relating to the method for producing olefins.

[0125] In a third embodiment, the implementation process according to this embodiment includes the crude olefin production step, the catalyst regeneration step, and the hot air generation step. The hot air generation step is the same as that described in the embodiment relating to the method for producing olefins.

[0126] The implementation steps according to this embodiment include the separation step as a fourth aspect. The separation step is the same as that described in the embodiment relating to the method for producing olefins.

[0127] The implementation process according to this embodiment, when carried out in the manner described above, allows for control of the flow rate or ratio of ethylene and propylene obtained by catalytic cracking, even when using waste plastic raw materials.

[0128] It should be noted that the method for producing olefins and the implementation steps according to the present invention are not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the present invention. Furthermore, configurations, methods, etc., of embodiments other than those described above may be arbitrarily adopted and combined.

[0129] The present invention will be described more specifically below with reference to examples. The present invention is not limited to these examples.

[0130] The hydrocarbon oils and kerosene used in each example and reference example are as follows:

[0131] <Hydrogen oils>

[0132] The hydrocarbon oil was obtained by thermal decomposition of polyolefin-based plastic, which mimics waste plastic. The hydrocarbon oil has a density of 0.780 g / cm³. ３ At 15°C, the refractive index was 1.45, and the main component was hydrocarbons with 5 to 20 carbon atoms, with an average carbon number of 12.9. The main component and average carbon number were determined by gas chromatography (GC-FID).

[0133] <Kerosene> Kerosene manufactured by Kanto Chemical Co., Ltd. was used.

[0134] (Example 1) A stainless steel reaction tube with an inner diameter of 16 mm and a total length of approximately 63 cm was filled with 3 g of zeolite catalyst. A mixture of hydrocarbon oil and kerosene in a mass ratio of 5:5 was used as the raw material for catalytic cracking. The raw material feed rate was set to approximately 0.30 g / min, and nitrogen gas (30 mL / min) and water (0.08 mL / min) were supplied along with the raw material for catalytic cracking, with a gravitational space velocity (WHSV) of 6.0 h. －１ The reaction temperature was raised to 600°C by heating the catalyst layer inside the reaction tube in an electric furnace.

[0135] After the catalytic cracking reaction was complete, the gaseous and liquid reaction products were recovered from the stainless steel reaction tube. The sampling time for the gaseous reaction product was set to 10 to 35 minutes, and the sampling time for the liquid reaction product was set to 20 to 35 minutes.

[0136] Each recovered component was analyzed using gas chromatography (GC-FID). Components such as C2' (ethylene) and C3' (propylene) were quantified using calibration with standard samples, and the C2' yield (mass%), C3' yield (mass%), the sum of the C2' and C3' yields, and the C3' / C2' ratio were calculated.

[0137] (Example 2) The procedure was the same as in Example 1, except that the mass ratio of hydrocarbon oil to kerosene was 9:1 and the reaction temperature was 550°C.

[0138] (Example 3) The procedure was the same as in Example 1, except that the mass ratio of hydrocarbon oil to kerosene was 1:9 and the reaction temperature was 650°C.

[0139] (Reference Example 1) The procedure was carried out in the same manner as in Example 1, except that hydrocarbon oil alone was used as the raw material for catalytic cracking instead of a mixture of hydrocarbon oil and kerosene.

[0140] (Reference Example 2) The procedure was the same as in Reference Example 1, except that the reaction temperature was set to 550°C.

[0141] (Reference Example 3) The procedure was the same as in Reference Example 1, except that the reaction temperature was set to 650°C.

[0142] (Reference Example 4) The procedure was carried out in the same manner as in Example 1, except that kerosene alone was used as the raw material for catalytic cracking instead of a mixture of hydrocarbon oil and kerosene.

[0143] The results for each example and reference example are shown in Table 1.

[0144]

[0145] Table 1 shows that, according to the results of Reference Examples 1 to 3, the C3' / C2' ratio can be lowered by increasing the reaction temperature, and the C3' / C2' ratio can be increased by lowering the reaction temperature. In other words, it can be seen that the amount of C2' component produced can be increased by increasing the reaction temperature. This trend is also reflected in the results of each example.

[0146] Furthermore, in the reference examples that do not include kerosene in the raw materials, there is variation in the change of the C3' / C2' ratio due to changes in reaction temperature. On the other hand, in the examples that include kerosene in the raw materials, the change in the C3' / C2' ratio due to changes in reaction temperature is constant, indicating that adding kerosene to the raw materials makes it easier to control the reaction temperature.

[0147] Furthermore, in each reference example that did not include kerosene in the raw materials, there was variation in the C3' + C2' yield due to changes in reaction temperature. On the other hand, in each example that included kerosene in the raw materials, the C3' + C2' yield remained constant regardless of the change in reaction temperature. In other words, from the results in Table 1, it can be said that by adding kerosene to the raw materials, it is possible to adjust the C3' / C2' ratio while suppressing fluctuations in yield due to changes in reaction temperature.

[0148] Comparing Example 2, which was carried out at a reaction temperature of 550°C, with Reference Example 2, although the C3' / C2' ratio in Example 2, which used kerosene, was lower, the C3' yield in Example 2 was relatively higher than in Reference Example 2, indicating an increase in the relative amount of C3' component produced. These results suggest that under relatively low temperature conditions such as 550°C, using kerosene can relatively increase the amount of C3' component produced.

[0149] Furthermore, comparing Example 3, which was carried out at a reaction temperature of 650°C, with Reference Example 3, it can be seen that the C3' / C2' ratio and C3' yield in Example 3, which used kerosene, are lower than those in Reference Example 3. This indicates that under relatively high temperature conditions such as 650°C, using kerosene can relatively increase the amount of C2' component produced.

[0150] From the above, as shown in the results in Table 1, it can be seen that by controlling the amount of kerosene added and the reaction temperature, the desired C3' / C2' ratio can be obtained even when there is variation in the quality of the hydrocarbon oil.

[0151] From the above, it can be seen that the present invention provides a method and process for producing olefins that allows control over the flow rate or ratio of ethylene and propylene obtained by catalytic cracking, even when using waste plastic raw materials.

Claims

1. A method for producing olefins, comprising: a thermal decomposition step of thermally decomposing a waste plastic raw material containing polyolefin to obtain a hydrocarbon flow; a crude olefin production step of supplying the hydrocarbon flow and kerosene and / or heavy oil to a catalytic cracking apparatus that decomposes hydrocarbons by contacting a catalyst containing zeolite with hydrocarbons to obtain crude olefins; a separation step of separating olefins having 2 to 4 carbon atoms from the crude olefins; and a catalyst regeneration step of regenerating the catalyst used in the crude olefin production step using a catalyst regeneration apparatus that regenerates the catalyst by heating, and returning the regenerated catalyst to the catalytic cracking apparatus, wherein in the crude olefin production step, the flow rates of ethylene and propylene in the crude olefins are measured, and at least one of the temperature of the catalytic cracking apparatus and the amount of kerosene and / or heavy oil supplied to the catalytic cracking apparatus are controlled based on the measured values.

2. The method for producing an olefin according to claim 1, further comprising a hot air generation step of generating hot air containing oxygen gas using a hot air generator, wherein in the catalyst regeneration step, the catalyst is heated using the hot air.

3. The method for producing an olefin according to claim 2, wherein the separation step is a step of further separating fuel oil and fuel gas from the crude olefin, and in the hot air generation step, at least a portion of the fuel oil and fuel gas is supplied to the hot air generator and used as fuel, and the temperature of the catalytic cracking apparatus is controlled based on the amount of fuel.

4. An implementation step for carrying out the method for producing an olefin according to any one of claims 1 to 3, the implementation step comprising the thermal decomposition step.

5. An implementation step for carrying out the method for producing an olefin according to any one of claims 1 to 3, comprising the crude olefin production step and the catalyst regeneration step.

6. An implementation step for carrying out the method for producing an olefin according to claim 2 or 3, comprising the crude olefin production step, the catalyst regeneration step, and the hot air generation step.

7. An implementation step for carrying out the method for producing an olefin according to any one of claims 1 to 3, the implementation step comprising the separation step.

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