A mild catalytic method for selectively producing aviation fuel from plastic waste.

Abstract

This disclosure relates to a catalytic method for producing sustainable aviation fuel from plastic waste. The method includes a step of obtaining sustainable aviation fuel by hydrocracking plastic waste under mild conditions in the presence of a catalyst, wherein the mild conditions are such that the plastic waste is hydrocracked at a temperature of less than 300°C, 2 × 10⁻⁶ 6 The process includes heating under a hydrogen pressure of Pa for no more than 3 hours, and the catalyst is a Rh-based bimetallic catalyst Rh2MoO x Rh2MoO2 is supported on an Al-SBA-15 material. x A method using a catalyst represented by / Al-SBA-15.

Description

[Technical Field]

[0001] This application claims priority to Singapore Patent Application No. 10202301879R, filed on 30 June 2023, the contents of which are incorporated herein by reference in their entirety for all purposes. [Background technology]

[0002] This disclosure generally relates to catalytic methods for producing aviation fuel from plastic waste. In particular, this disclosure relates to catalytic methods for producing sustainable aviation fuel from plastic waste under mild conditions in the presence of a catalyst. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] Plastics are widely used in automobiles, packaging, construction, and disposable protective equipment such as masks, leading to a rapid increase in both plastic use and plastic waste generation. However, plastic waste cannot be easily broken down by microorganisms and must be incinerated. This incineration process releases greenhouse gases, including carbon dioxide, contributing to global warming. This is a particularly pressing issue for small countries like Singapore, where land for landfill is limited. Addressing the plastic waste problem is crucial to mitigating environmental damage. One option is to convert plastic waste into useful products that society needs, such as sustainable aviation fuel (SAF).

[0004] Currently, aviation fuel is primarily refined from crude oil and natural gas, and the extraction, refining, and transportation processes of these fossil fuels emit enormous amounts of carbon dioxide. In contrast, sustainable aviation fuel produced from plastic waste can reduce the demand for crude oil and natural gas, thereby reducing carbon dioxide emissions throughout the entire aviation fuel production cycle. Although carbon dioxide is produced when SAF is consumed, the circular upcycling of plastic waste into SAF through economical and energy-efficient processes is a more sustainable interim solution. However, current methods for converting plastic waste into aviation fuel involve high-temperature processes such as pyrolysis or gasification.

[0005] In the pyrolysis process, organic materials, including plastic waste, are heated to temperatures typically ranging from 500 to 800°C in the absence of oxygen. In the gasification process, another high-temperature process, carbonaceous raw materials such as plastic waste are reacted with controlled amounts of oxygen and / or vapor at temperatures typically exceeding 700°C. Both processes enable the conversion of plastic waste into aviation fuel, but an additional hydrodeoxygenation / hydrogenation process is required to convert the unsaturated oil into a saturated product suitable for use as aviation fuel. In addition, working conditions such as temperature, pressure, and residence time must be carefully controlled to optimize product yield and quality while minimizing emissions and the enormous energy consumption due to the harsh temperature conditions.

[0006] Therefore, it is desirable to provide a method for producing sustainable aviation fuel from plastic waste. This method aims to address at least one of the problems described above, or at least provide an alternative. [Means for solving the problem]

[0007] According to a first aspect of this disclosure, a catalytic method for producing sustainable aviation fuel from plastic waste is provided. The method comprises the step of obtaining sustainable aviation fuel by hydrocracking plastic waste under mild conditions in the presence of a catalyst, wherein the mild conditions are such that the plastic waste is hydrocracked at a temperature of less than 300°C, 2 × 10⁻⁶ 6 The process includes heating under a hydrogen pressure of Pa for no more than 3 hours, and the catalyst is a Rh-based bimetallic catalyst Rh2MoO x Rh2MoO2 is supported on an Al-SBA-15 material. x This catalyst is represented as / Al-SBA-15.

[0008] In some embodiments, the sustainable aviation fuel described above comprises hydrocarbons with a carbon number in the range of 6 to 16.

[0009] In some embodiments, the hydrogenolysis is carried out in the absence of a solvent. According to a second aspect of this disclosure, an Rh-based bimetallic catalyst is provided for use in producing sustainable aviation fuel from plastic waste. The catalyst is Rh2MoO2 supported on an Al-SBA-15 material. x Includes Rh2MoO x It is represented as / Al-SBA-15. [Modes for carrying out the invention]

[0010] The following description provides illustrative methods, parameters, etc. Embodiments of the present invention are described in sufficient detail so that those skilled in the art can carry out the invention. Other embodiments can be adopted and structural and logical modifications can be made without departing from the scope of the invention. The embodiments are not necessarily mutually exclusive, and one or more embodiments can be combined with other embodiments to form new embodiments.

[0011] Features described in the context of one embodiment may equally apply to the same or similar features in other embodiments. Also, features described in the context of one embodiment may equally apply to other embodiments even if not explicitly described in those other embodiments. Furthermore, additions, combinations, and / or alternatives described for features in the context of one embodiment may equally apply to the same or similar features in other embodiments.

[0012] In the context of each embodiment, the articles "a", "an", and "the" used in relation to a feature or element are intended to refer to one or more of that feature or element.

[0013] In the context of each embodiment, the terms "about" or "approximately" used in relation to a numerical value are intended to include its exact value and a reasonable range of variation, for example, including variations within 10% of the stated value.

[0014] As used herein, the term "and / or" is intended to include all combinations of one or more of the associated listed items.

[0015] "Comprising" means including, but not limited to, what follows the term "comprising". Thus, the use of the term "comprising" indicates that the listed elements are necessary or essential, but other elements are optional and may or may not be present.

[0016] "Consisting of" means including and limited to what follows the phrase "consisting of". Thus, the phrase "consisting of" indicates that the listed elements are necessary or essential and that no other elements may be present.

[0017] This disclosure relates to a highly selective catalytic method for producing sustainable aviation fuel (SAF) from plastic waste.

[0018] In this specification, the term “plastic waste” means plastic material that has been discarded, unused, or no longer needed, and whose usable life has ended and is no longer required. Examples include plastic packaging, bottles, bags, containers, and other single-use plastic products that are disposed of after use. Plastics are made from a wide range of organic polymers, including, but not limited to, polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). In some preferred embodiments, the plastic waste is polypropylene (PP).

[0019] In this specification, the term “sustainable aviation fuel” refers to hydrocarbons with 6 to 16 carbon atoms, with the primary range of products being 8 to 16 carbon atoms.

[0020] According to a first aspect of this disclosure, the catalytic method includes a step of obtaining sustainable aviation fuel by hydrocracking plastic waste under mild conditions in the presence of a catalyst, wherein the mild conditions involve hydrocracking the plastic waste at a temperature of less than 300°C, 2 × 10⁻⁶ 6 The process includes heating under a hydrogen pressure of Pa (20 bar) for no more than 3 hours, and the catalyst is a Rh-based bimetallic catalyst Rh2MoO x Rh2MoO2 is supported on an Al-SBA-15 material. x This catalyst is represented as / Al-SBA-15.

[0021] As used herein, the term "Al-SBA-15" refers to a type of mesoporous support. This corresponds to the Santa Barbara Amorphous (SBA) mesoporous silica system, and aluminum (Al) is incorporated into the framework of SBA-15. In some embodiments, the Al-SBA-15 support has a pore structure with high regularity and uniform pore diameters in the range of 2 - 30 nm.

[0022] Rh2MoO, a Rh-based bimetallic catalyst x is a mixed metal oxide catalyst containing rhodium (Rh) and molybdenum (Mo). In Rh2MoO x the value of x varies depending on the specific synthesis method and synthesis conditions used in the preparation of the catalyst. In some embodiments, the value of x is in the range of 2 - 3.

[0023] In some embodiments, the sustainable aviation fuel contains hydrocarbons in the range of 6 - 16 carbon atoms, and the main range of the products is 8 - 16 carbon atoms.

[0024] In some embodiments, hydrocracking is carried out in the absence of a solvent. Performing hydrocracking without using a solvent contributes to improving efficiency as there is no waste solvent to be disposed of after the production of sustainable aviation fuel by the method of the present disclosure, making it easier to reduce operating costs.

[0025] In some embodiments, the catalyst represented by Rh2MoO x / Al-SBA-15 has a metal loading in the range of 0.5 - 3 wt% based on the total weight of the catalyst. In some embodiments, the ratio of the amounts of Rh (rhodium) and Mo (molybdenum) supported on the support material is 2:5.

[0026] In some embodiments, the plastic waste is a single-component plastic selected from the group consisting of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). In some preferred embodiments, the plastic waste is polypropylene (PP).

[0027] The method of this disclosure yields an organic oil product containing saturated hydrocarbons in the range of 6 to 35 carbon atoms, as well as a gaseous product and a solid residue, achieving a relatively high yield of approximately 94% (Table 1, Case 2). In some embodiments, the method of this disclosure produces sustainable aviation fuel from plastic waste, consisting of hydrocarbons in the range of 6 to 16 carbon atoms (the main range of the product is 8 to 16 carbon atoms), with an average yield of approximately 83 wt%. The remaining organic oil product consists mainly of 6% hydrocarbons with 17 to 20 carbon atoms and 2% hydrocarbons with 21 to 35 carbon atoms, equivalent to motor oil. The gaseous product produced by this method consists of low molecular weight hydrocarbons with 1 to 4 carbon atoms and unreacted hydrogen.

[0028] Unlike conventional methods, the method of this disclosure yields sustainable aviation fuel with 8 to 16 carbon atoms in relatively high yields using mild reaction conditions. This is in contrast to conventional methods, which require harsher conditions and longer reaction times to achieve similar results. The technology of this disclosure has the potential to accelerate the greening of air traffic and speed up the transition to more environmentally friendly, renewable alternative aviation fuels. Furthermore, the technology of this disclosure offers an alternative solution for plastic waste management and contributes to the realization of "zero waste" initiatives.

[0029] According to aspects of this disclosure, an Rh-based bimetallic catalyst is provided for use in producing sustainable aviation fuel from plastic waste. The Rh-based bimetallic catalyst is Rh2MoO2 supported on an Al-SBA-15 material. x Includes Rh2MoO x It is represented as / Al-SBA-15.

[0030] In some embodiments, the catalyst is prepared by the following procedure: ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 A solution containing (4H2O) is mixed with Al-SBA-15, and this mixture is passed through a rotary evaporator to obtain a solid residue. After drying the solid residue, it is calcined in a furnace to obtain MoO x / Al-SBA-15 is obtained. Prepare a precursor solution of Rh(NO3)3, and add MoO to this precursor solution. x / Al-SBA-15 is added and mixed. The mixture is then passed through a rotary evaporator to obtain a solid residue. After drying the solid residue, it is calcined in a furnace to obtain RhMoO x / Al-SBA-15 is obtained. Subsequently, the solid catalyst is reduced under a hydrogen gas atmosphere to obtain the final active catalyst, Rh2MoO x Obtain Al-SBA-15.

[0031] In some embodiments, the catalyst has a metal loading amount in the range of 0.5 to 3 wt% relative to the total weight of the catalyst. This metal loading amount is lower than that of catalysts known in the art, and is about a fraction of that.

[0032] Furthermore, the catalysts of this disclosure reduce reaction time to approximately 1 / 5 to 1 / 24 and reaction pressure to 1 / 2 to 1 / 3 compared to catalysts known in the art. The catalysts are reusable while maintaining the high selectivity and high yield of sustainable aviation fuel. Methane fuel is also produced when converting plastic waste into sustainable aviation fuel. Since methane fuel can be used to generate the hydrogen gas required for the hydrocracking process, a self-sufficient system for producing sustainable aviation fuel from plastic waste can be established.

[0033] The catalysts and catalytic processes described herein represent a groundbreaking advance in converting plastic waste into valuable fuel. With a high yield of approximately 83 wt% for sustainable aviation fuel derived from plastic waste, these technologies can contribute to reducing plastic waste and promoting a circular economy. Furthermore, as the focus shifts from crude oil and natural gas extraction to the production of aviation and gaseous fuels, these methods offer a sustainable alternative in fuel production. The methods also streamline production by reducing overall operating costs.

[0034] To facilitate understanding of this disclosure, specific examples of embodiments are provided below. These embodiments should not be construed as limiting or defining the entire scope of this disclosure. Those skilled in the art will understand that the embodiments described below are not an exhaustive list of embodiments of this disclosure. [Examples]

[0035] Example 1 Catalyst Rh2MoO x Preparation of Al-SBA-15

[0036] The catalyst is Rh2MoO x Al-SBA-15 was prepared as follows: First, 0.20 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 The precursor was completely dissolved by adding 4H2O to 20 mL of deionized water in a round-bottom flask and stirring for 30 minutes. Then, Al-SBA-15 (1 g) was added to the solution and the mixture was stirred at room temperature for 3 hours. After that, the mixture was passed through a rotary evaporator to remove the deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. The dried solid was then placed in a box furnace, the furnace temperature was increased at 10 K / min, and it was calcined at 500°C for 3 hours to obtain MoO2. x Al-SBA-15 was obtained. 0.08 mmol of Rh(NO3)3 precursor solution was added to 20 mL of deionized water in a round-bottom flask and stirred for 30 minutes. Subsequently, MoO x / Al-SBA-15 (1 g) was added to the solution and the mixture was stirred at room temperature for 3 hours. Then, the mixture was passed through a rotary evaporator to remove deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. Then, the dried solid was placed in a box oven, the oven temperature was increased at 10 K / min, and it was calcined at 500°C for 3 hours to obtain RhMoO x / Al-SBA-15 was obtained. Subsequently, the temperature was increased at 1°C / min under a hydrogen gas atmosphere, and the solid catalyst was reduced at 300°C for 30 minutes to obtain the final active catalyst, Rh2MoO x / Al-SBA-15 was obtained.

[0037] Example 2 Preparation of other catalysts

[0038] Other catalysts supported on SBA-15 were prepared in the same manner as in Example 1. Specifically, 0.20 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 The precursor was added to 20 mL of deionized water in a round-bottom flask and stirred for 30 minutes to completely dissolve it. Then, 1 g of SBA-15 was added to the solution and the mixture was stirred at room temperature for 3 hours. After that, the mixture was passed through a rotary evaporator to remove the deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. Then, the dried solid was placed in a box furnace, the furnace was heated at 10 K / min, and calcined at 500°C for 3 hours to obtain MoO2. x / SBA-15 was obtained. 0.08 mmol of Rh(NO3)3 precursor solution was added to 20 mL of deionized water in a round-bottom flask and stirred for 30 minutes. Subsequently, MoO x / SBA-15 (1g) was added to the solution and the mixture was stirred at room temperature for 3 hours. Then, the mixture was passed through a rotary evaporator to remove deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. Then, the dried solid was placed in a box oven, the oven temperature was increased at 10K / min, and it was calcined at 500°C for 3 hours to obtain RhMoO2. x / SBA-15 was obtained. Subsequently, the solid catalyst was reduced by heating at 1°C / min under a hydrogen gas atmosphere and at 300°C for 30 minutes, thereby obtaining the final active catalyst, Rh2MoO xI obtained / SBA-15.

[0039] Other catalysts supported on LaP3 were prepared in the same manner as in Example 1. Specifically, 0.20 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 The precursor was added to 20 mL of deionized water in a round-bottom flask and stirred for 30 minutes to completely dissolve it. Then, 1 g of LaP3 was added to the solution and the mixture was stirred at room temperature for 3 hours. After that, the mixture was passed through a rotary evaporator to remove the deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. The dried solid was then placed in a box furnace, the furnace was heated at 10 K / min, and calcined at 500°C for 3 hours to obtain MoO2. x / LaP3 was obtained. 0.08 mmol of Rh(NO3)3 precursor solution was added to 20 mL of deionized water in a round-bottom flask and stirred for 30 minutes. Subsequently, 1 g of MoO x / LaP3 was added to the solution and the mixture was stirred at room temperature for 3 hours. Then, the mixture was passed through a rotary evaporator to remove deionized water and obtain a solid residue. The solid residue was dried overnight in an oven at 80°C. Then, the dried solid was placed in a box oven, the oven temperature was increased at 10K / min, and it was calcined at 500°C for 3 hours to obtain RhMoO2. x / LaP3 was obtained. Subsequently, the solid catalyst was reduced by heating at 1°C / min under a hydrogen gas atmosphere and at 300°C for 30 minutes, thereby obtaining the final active catalyst, Rh2MoO x / LaP3 was obtained.

[0040] Example 3 Converting polypropylene (PP) waste into sustainable aviation fuel (SAF)

[0041] The hydrocracking of polypropylene (PP) waste was carried out in a 160 mL Parr autoclave equipped with an overhead mechanical stirrer on its rotor. PP (approximately 0.9-1.1 g) was treated with the catalyst Rh2MoO2. xIn addition to Al-SBA-15 (approximately 0.9-1.1 g), the mixture was purged with argon and hydrogen gas for three cycles. The Parr reactor was then pressurized with hydrogen gas (20 bar) and heated at 300°C for 3 hours with stirring. The reactor was allowed to cool slowly. The pressure difference was measured before collecting the gas in the reactor headspace into a gas bag. 20 mL of dichloromethane (DCM) was added to the crude mixture, and the liner was washed with DCM to prevent loss of the oily product. The resulting mixture was filtered to remove solid residue. This solid residue was dried overnight in a 70°C oven. The solid residue was subjected to pyrolysis gas chromatography-mass spectrometry to obtain the hydrocarbon distribution. The recovered gas was analyzed by GC-FID and GC-TCD for quantification. The clear filtrate was passed through a rotary evaporator to remove all present DCM, obtaining a colorless oily product. The final mass of the oily product was recorded. A known amount (average 0.01 mmol) of octacosane, an internal standard, was dispersed in 3 mL of DCM and added to 0.2–0.3 g of an oily mixture. The oily product was then analyzed by GC-MS, GC-FID, pyrolysis gas chromatography-mass spectrometry, and high-temperature gel permeation chromatography (HT-GPC). These procedures were repeated for other catalysts. The results are shown in Table 1.

[0042] [Table 1]

[0043] In the examples shown above, the reaction conditions used for converting polypropylene (PP), which is plastic waste, to SAF were as follows: the plastic waste was heated to a temperature of less than 300°C, and 2 × 10⁻⁶ 6 This includes heating under a hydrogen pressure of Pa (20 bar) for no more than 3 hours. According to the results in Table 1, Rh2MoO2 was used as a catalyst in the hydrocracking process. xUsing / Al-SBA-15, relatively high conversion rates (96% and 89%) and relatively high yields (94% and 71%) of oily products in the C6-C35 range can be achieved. The yield of SAF in the C6-C16 range accounts for approximately 83 wt% of the total SAF, with the remainder consisting mainly of 6% hydrocarbons with C17-C20 and 2% hydrocarbons with C21-C35 equivalent to motor oil. This yield is among the highest levels known in the art for selectively producing C6-C16 SAF, and achieving similar results with conventional methods requires harsher conditions and longer reaction times.

[0044] While embodiments of the present invention have been disclosed and described, the present invention is not limited to these embodiments. Those skilled in the art will understand that various modifications and variations are possible with respect to the embodiments of the present invention without departing from the scope of the invention. The scope of the present invention is defined by the scope set forth in the following claims.

Claims

1. A catalytic method for producing sustainable aviation fuel from plastic waste, The process includes obtaining sustainable aviation fuel by hydrocracking plastic waste under mild conditions in the presence of a catalyst. The aforementioned mild conditions involve heating plastic waste at a temperature below 300°C, 2 × 10 ６ This includes heating under a hydrogen pressure of Pa for no more than 3 hours. The catalyst is a Rh-based bimetallic catalyst Rh2MoO ｘ Rh2MoO2 is supported on Al-SBA-15 material. ｘ A method using a catalyst represented by Al-SBA-15.

2. The catalyst method according to claim 1, wherein the sustainable aviation fuel comprises hydrocarbons having 6 to 16 carbon atoms.

3. The catalytic method according to claim 1, wherein the hydrogenolysis is carried out in the absence of a solvent.

4. The catalyst method according to claim 1, wherein the amount of metal supported on the catalyst is in the range of 0.5 to 3 wt% relative to the total weight of the catalyst.

5. The catalytic method according to claim 1, wherein the plastic waste is a plastic consisting of a single component selected from the group consisting of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET).

6. The catalyst method according to claim 1, for producing sustainable aviation fuel with an average of 83 wt% from the aforementioned plastic waste.

7. A Rh-based bimetallic catalyst used to produce sustainable aviation fuel from plastic waste, comprising Rh2MoO2 supported on an Al-SBA-15 material. ｘ Includes Rh2MoO ｘ A catalyst represented as Al-SBA-15.

8. The catalyst according to claim 7, wherein the amount of metal supported on the catalyst is in the range of 0.5 to 3 wt% relative to the total weight of the catalyst.

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