Method for producing synthetic gas from plastic and high-entropy oxide

Abstract

The present application relates to a kind of synthetic gas from plastic and high-entropy oxide.The synthetic gas from plastic of the present application includes the following steps: plastic is contacted with high-entropy oxide and carries out chemical chain gasification reaction, wherein the plastic is selected from one or more of polyolefin, polystyrene, polyester, halogenated olefin treated by dehalogen process;The composition of the high-entropy oxide is Ni a Co b Fe c M d Al e O x Wherein M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, x is 1.3~5.8.The method of the present application has high syngas yield and high CO selectivity.The high-entropy oxide of the present application has high stability, is easy to regenerate and has high cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to a method for producing syngas from plastics and high-entropy oxides. Background Technology

[0002] Because plastics are widely used in various fields such as industry, agriculture, and daily life, the current method of treating waste plastics is to landfill or incinerate them along with other waste generated in these fields. This method has obvious drawbacks. Waste plastics have a complex composition, but most are rich in C, H, and O. Therefore, producing syngas from waste plastics can significantly improve atom economy; moreover, syngas is an important chemical raw material with a mature downstream application market, which can further extend the carbon cycle process.

[0003] Chemical looping gasification (CLG) technology generates syngas primarily composed of H2 and CO by reacting hydrocarbons produced from the pyrolysis of waste plastics with lattice oxygen in an oxygen carrier. This avoids the N2 dilution problem caused by the direct involvement of air in traditional gasification processes, significantly improving syngas quality. The oxygen carrier is crucial to CLG technology, with Fe2O3 being a representative example. To enhance its stability, composite metal oxides are often constructed to modulate the activity of the lattice oxygen.

[0004] For example, Patent Document 1 discloses a spinel-type iron-based oxygen carrier (Cu 0.2 Mn 0.2 Ni 0.2 Ca 0.2 Sr 0.2 Fe2O4 can significantly improve the performance of polypropylene chemical looping gasification for hydrogen production. Patent document 2 discloses an oxygen carrier using activated alumina spheres as a support and any two composite metals of iron, cobalt, nickel, and copper as active components, for use in polypropylene steam chemical looping gasification for hydrogen production. Patent document 3 discloses a transition metal high-entropy oxygen carrier with the composition (MnFeCoNiCu)O. 4-x or (MnFeCoNiCu)O 4-x / M (M = ZrO2, CeO2, MgO, Y2O3, or Er2O3), this transition metal high-entropy oxygen carrier can be applied to biomass chemical looping gasification reactions, but the syngas yield and CO selectivity need to be improved. It is evident that high-entropy oxides have great potential as oxygen carriers, but require ingenious composition design.

[0005] References

[0006] Patent Document 1: CN 119660813 A;

[0007] Patent Document 2: CN 119931738 A;

[0008] Patent document 3: CN 117019168 A. Summary of the Invention

[0009] The problem the invention aims to solve

[0010] The oxygen carriers with specific crystal structures disclosed in Patent Documents 1 and 2 are prone to strong phase transitions under high-temperature reaction conditions, and it is difficult to completely restore the original structure through oxidative regeneration, making it difficult to meet the requirements for multiple cycles. Although the high-entropy oxide disclosed in Patent Document 3 has attracted attention due to its high stability, there is still considerable room for improvement in its syngas yield and CO selectivity.

[0011] Therefore, there is still an urgent need to develop a method for producing syngas from plastics that utilizes high-entropy oxides as oxygen carriers. This method offers high syngas yield and high CO selectivity, and the high-entropy oxides used as oxygen carriers exhibit high stability, ease of regeneration, and high cycle stability.

[0012] Solution for solving the problem

[0013] To address the aforementioned problems, the inventors conducted long-term and in-depth research and discovered that when high-entropy oxides composed of specific metals are used to produce syngas from plastics via chemical looping gasification, the syngas yield is high and the CO selectivity is high. Furthermore, it was found that the high-entropy oxides have high stability, are easy to regenerate, and have high cycle stability, thus completing this invention.

[0014] Specifically, the present invention solves the problems of the present invention through the following solutions.

[0015] [1] A method for producing syngas from plastic, comprising the following steps:

[0016] This allows the plastic to undergo a chemical chain vaporization reaction by contacting high-entropy oxides.

[0017] The plastic is selected from one or more of polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins;

[0018] The high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.8.

[0019] [2] According to the method described in [1], the mass ratio of plastic to high-entropy oxide is 1:(1~10).

[0020] [3] According to the method of [1] or [2], wherein the chemical looping gasification reaction is carried out at 700~1000°C.

[0021] [4] According to the method of [1] or [2], wherein, during the chemical chain gasification reaction, no oxygen, water vapor and CO2 are added to the reaction system.

[0022] [5] According to the method of [1] or [2], wherein the plastic is one or more selected from polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), dechlorinated polyvinyl chloride (dechlorinated PVC).

[0023] [6] According to the method of [1] or [2], wherein the method further includes the following steps: after the chemical looping gasification reaction is completed, the high-entropy oxide is regenerated to obtain the regenerated high-entropy oxide, wherein the regeneration of the high-entropy oxide is carried out in the presence of an oxidant;

[0024] Preferably, the oxidant is one or more selected from air, water vapor, and carbon dioxide;

[0025] Preferably, the regeneration of the high-entropy oxide is carried out at a temperature of 750~1050°C.

[0026] [7] According to the method of [5], the method further includes the step of: contacting the regenerated high-entropy oxide with the plastic to carry out a chemical chain gasification reaction, wherein the plastic is one or more selected from polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins.

[0027] [8] The high-entropy oxide is used in the production of syngas from plastics, wherein the high-entropy oxide has a composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.8.

[0028] [9] A high-entropy oxide with the composition Ni a Co b Fe c M d Al e O xWhere M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.8.

[0029]

[10] The method according to [1], the use according to [8], or the high entropy oxide according to [9], wherein the ratio of a:b:c:d:e is (0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2), preferably (0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1).

[0030] The effects of the invention

[0031] The method for producing syngas from plastics according to the present invention (hereinafter also referred to as "the method of the present invention") has high syngas yield and high CO selectivity. For example, when using polyethylene or polypropylene as raw materials, the syngas yield is as high as 70 mmol or more per gram of plastic, and the CO selectivity is increased to over 90%. In addition, the method of the present invention can obtain high-yield syngas without the need to add additional gasifying agents such as oxygen, water vapor, and CO2 during the gasification stage.

[0032] The high-entropy oxide used in this invention has strong anti-sintering ability and good thermal stability. The raw materials are cheap and readily available, the preparation method is simple, and the equipment requirements are low, making it suitable for large-scale production. Furthermore, when used in the method of this invention, it has low surface carbon, is easy to regenerate, and has high cycle stability. For example, after 10 cycles, the decrease in syngas yield is less than 3%. Attached Figure Description

[0033] Figure 1 This is a bar chart showing the syngas yield and carbon conversion data from the 10 cyclic experiments in Example 1. Detailed Implementation

[0034] The present invention will now be described in detail. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples.

[0035] <Terminology and Definitions>

[0036] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0037] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0038] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0039] In this specification, the terms "optionally" or "optionally" are used to indicate the use or non-use of certain substances, components, procedures, application conditions, etc.

[0040] All unit names used in this manual are international standard unit names, and unless otherwise stated, the "%" indicates weight or mass percentage.

[0041] In this specification, references to "preferred embodiments," "implementation methods," etc., mean that a specific element (e.g., feature, structure, property, and / or characteristic) related to that embodiment is included in at least one of the embodiments described herein, and may or may not be present in other embodiments. Furthermore, it should be understood that the elements may be combined in any suitable manner in various embodiments.

[0042] One object of the present invention is to provide a method for producing syngas from plastics, comprising the following steps:

[0043] This allows the plastic to undergo a chemical chain vaporization reaction by contacting high-entropy oxides.

[0044] The plastic is selected from one or more of polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins;

[0045] The high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.8.

[0046] This invention utilizes high-entropy oxides composed of specific metals to produce syngas from plastics via chemical looping gasification, resulting in high syngas yield, high CO selectivity, and high stability, easy regeneration, and high cycle stability of the high-entropy oxides.

[0047] In some embodiments, the method of the present invention further includes the following steps: after the chemical looping gasification reaction is completed, regenerating the high-entropy oxide to obtain regenerated high-entropy oxide, wherein the regeneration is carried out in the presence of an oxidant.

[0048] In some embodiments, the method of the present invention further includes the step of contacting the regenerated high-entropy oxide with the plastic to carry out a chemical chain gasification reaction.

[0049] The various aspects of the method of the present invention will be described in detail below.

[0050] <High-entropy oxides>

[0051] Preferably, the high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.4~0.8, b is 0.4~0.8, c is 0.4~0.8, d is 0.4~0.8, e is 0.4~0.8, a+b+c+d+e is 2~4, and x is 2.6~5.2.

[0052] Preferably, the high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.5~0.7, b is 0.5~0.7, c is 0.5~0.7, d is 0.5~0.7, e is 0.5~0.7, a+b+c+d+e is 2.5~3.5, and x is 3.25~4.55.

[0053] Preferably, the high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.4~0.7, b is 0.4~0.7, c is 0.5~0.7, d is 0.6~0.8, e is 0.6~0.8, and x is 3.25~4.6.

[0054] Preferably, the ratio of a:b:c:d:e is (0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2), more preferably (0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1).

[0055] Most preferably, the high-entropy oxide is Ni. 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al0.6 O4.

[0056] The high-entropy oxides used in this invention can be prepared by conventional methods, such as sol-gel method, co-precipitation method or high-temperature solid-phase method.

[0057] In some embodiments, the method for preparing the high-entropy oxide used in this invention includes the following steps:

[0058] (1) Dissolve the water-soluble salt of the metal contained in the high-entropy oxide in water, then add citric acid or ammonium citrate, and then heat to 75~95℃ and keep for 4~24 hours to obtain wet gel;

[0059] (2) The wet gel is placed in air at 100~115℃ and dried for 8~30 hours to obtain a dry gel;

[0060] (3) Calcine the dry gel in air at 800~1000℃ for 4~8 hours.

[0061] Preferably, the water-soluble salt is one or more selected from nitrates, chlorides, and hydrates of nickel, cobalt, iron, magnesium, zinc, and aluminum, including but not limited to nickel nitrate, cobalt nitrate, iron nitrate, magnesium nitrate, zinc nitrate, aluminum nitrate, and their various hydrates, as well as nickel chloride, cobalt chloride, iron chloride, magnesium chloride, zinc chloride, and aluminum chloride.

[0062] <Plastics>

[0063] The plastic used in the method of the present invention is one or more selected from polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins.

[0064] Examples of polyolefins include, but are not limited to, polyethylene, polypropylene, polybutene, polyisobutylene, polymethylpentene, polybutadiene, polyisoprene, and various copolymers of the olefin monomers that form the above polyolefins (e.g., ethylene-propylene copolymers, ethylene-octene copolymers, polyolefin elastomers (POE), etc.), as well as copolymers of these olefin monomers with cyclic olefins (e.g., ethylene-norbornene copolymers), etc.

[0065] Examples of polyesters include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polycaprolactone, polylactic acid, polyglycolic acid, and poly(butylene adipate / terephthalate).

[0066] Examples of polyhalogenated olefins include, but are not limited to, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, and fluororubber.

[0067] Preferably, the plastic is waste plastic. In this document, "waste plastic" refers to plastic products or materials that have been discarded or are no longer used during production, distribution, consumption, or use. These plastics have typically lost their original purpose and are classified as solid waste.

[0068] Waste plastics come from a wide range of sources, including daily life, industrial production, agriculture, and healthcare. In daily life, examples include used plastic bags, packaging films, beverage bottles, disposable tableware, discarded toys, synthetic fabrics, and plastic casings from household appliances. In industrial production, examples include plastic scraps, substandard products, and packaging materials generated in factories. In agriculture, examples include agricultural mulch film, greenhouse film, seedling pots, and fertilizer packaging. In healthcare, examples include medical devices (such as syringes and infusion bags).

[0069] The method of the present invention can achieve efficient and economical resource utilization of waste plastics by preparing syngas from plastics.

[0070] <Chemical chain gasification reaction>

[0071] In the method of the present invention, the plastic is converted into syngas by contacting it with a high-entropy oxide to carry out a chemical chain gasification reaction.

[0072] Preferably, the molar ratio of oxygen in the high-entropy oxide to carbon in the plastic is O / C = 0.1~3, more preferably 0.2~2, more preferably 0.3~1.5, and also preferably 0.4~1.3, such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, etc.

[0073] Preferably, the mass ratio of plastic to high-entropy oxide is 1:(1~10), more preferably 1:(2~9), more preferably 1:(2.5~8), and even more preferably 1:(3~7).

[0074] Preferably, the reaction temperature of the chemical looping gasification reaction is 700~1000℃, more preferably 750~950℃, such as 800℃, 820℃, 850℃, 920℃, etc.

[0075] Preferably, during the chemical looping gasification reaction, no gasifying agent is added to the reaction system, and in particular, no oxygen, water vapor, or CO2 is added to the reaction system.

[0076] Preferably, the chemical looping gasification reaction is carried out in an inert gas (e.g., nitrogen, argon, helium), that is, apart from the gas produced by the reaction, the reaction system contains only (i.e., more than 98 mol% is) inert gas.

[0077] In a preferred embodiment, the plastic is mixed with a high-entropy oxide and heated to the reaction temperature in an inert gas atmosphere to carry out a chemical chain gasification reaction.

[0078] The reaction can be carried out in any suitable reactor, including but not limited to fixed-bed reactors, fluidized-bed reactors, rotary kiln reactors, etc.

[0079] <Regeneration>

[0080] The high-entropy oxides used in the method of this invention can be easily regenerated after the chemical looping gasification reaction is completed, thereby allowing for reuse, reducing costs, and improving environmental friendliness.

[0081] Preferably, the used high-entropy oxide is regenerated by contacting it with an oxidant.

[0082] Preferably, the oxidant is one or more selected from air, water vapor, and carbon dioxide. Air is preferred from the perspectives of ease of operation and cost.

[0083] Preferably, regeneration is carried out at 750~1050°C.

[0084] In some implementations, after the chemical looping gasification reaction is completed, the used high-entropy oxides are transported from the chemical looping gasification reactor to a regeneration reactor for regeneration.

[0085] In some implementations, after the chemical looping gasification reaction is completed, the syngas in the reactor is discharged, and then an oxidant is added to regenerate the high-entropy oxides.

[0086] <Loop>

[0087] In some implementations, the regenerated high-entropy oxides are reused in the chemical looping gasification reaction, thereby achieving the recycling of high-entropy oxides and improving the economic and environmental friendliness of the method of the present invention.

[0088] In this article, one regeneration and one reuse are referred to as a cycle.

[0089] Preferably, the method of the present invention includes 1 to 50 cycles, more preferably 2 to 40 cycles, more preferably 3 to 30 cycles, such as 4 to 20 cycles, 5 to 15 cycles, etc.

[0090] In some implementations, after regeneration is complete, the remaining oxidant in the reactor is discharged, and then an inert gas and plastic are added for the next chemical looping gasification reaction.

[0091] In some implementations, the regenerated high-entropy oxides in the regeneration reactor are fed into the reactor for a chemical looping gasification reaction and mixed with plastics for the next chemical looping gasification reaction.

[0092] In some embodiments, the method of the present invention is carried out as a continuous process, wherein the used high-entropy oxides are continuously fed to a regeneration reactor for regeneration, and the regenerated high-entropy oxides are continuously fed to a chemical looping gasification reactor, while the plastics are continuously fed to the chemical looping gasification reactor.

[0093] The regeneration of high-entropy oxides and the chemical looping vaporization reaction in each cycle are described above.

[0094] Example

[0095] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0096] Example 1

[0097] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:1, and dissolve them in deionized water, stirring until completely dissolved. Add citric acid in a molar ratio of 1.2 times the total number of metal cations and stir until completely dissolved. Place the solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 900℃ in air for 5 h to obtain the high-entropy oxide oxygen carrier Ni. 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 O4.

[0098] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 6.1:1). 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 After the high-entropy oxide oxygen carrier (O4) is thoroughly mixed with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.), it is placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas is then introduced into the closed fixed-bed reactor, and after heating to 900°C, the basket is quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 30 minutes while the gas is collected.

[0099] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 900°C for 40 minutes. The regenerated oxygen carrier was then mixed with waste polypropylene plastic again for a second cycle experiment; this process was repeated 10 times.

[0100] Example 2

[0101] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:1, and dissolve them in deionized water, stirring until completely dissolved. Add citric acid in a molar ratio of 1.2 times the total number of metal cations and stir until completely dissolved. Place the solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 900℃ in air for 5 h to obtain the high-entropy oxide oxygen carrier Ni. 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 O4.

[0102] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 6.1:1). 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 After the high-entropy oxide oxygen carrier (O4) is thoroughly mixed with polyethylene (PE, manufactured by Sinopec Maoming Petrochemical Co., Ltd.), it is placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas is then introduced into the closed fixed-bed reactor, and after heating to 900°C, the basket is quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 30 minutes while the gas is collected.

[0103] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 900°C for 40 minutes.

[0104] Example 3

[0105] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:1, and dissolve them in deionized water, stirring until completely dissolved. Add citric acid in an amount equal to 1.2 times the total number of metal cations and stir until completely dissolved. Place the solution on a heated stirring table and evaporate at 80°C for 24 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110°C for 10 h to obtain a dry gel. Calcinate the dry gel at 900°C in air for 5 h to obtain a high-entropy oxide oxygen carrier Ni. 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 O4.

[0106] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 6.4:1). 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 The high-entropy oxide oxygen carrier (O4) was mixed evenly with a plastic mixture (PP, PE, PS, PET, and dechlorinated PVC in a mass ratio of 1:1:1:1:1, all manufactured by China Petrochemical Corporation Maoming Petrochemical Co., Ltd.), and then placed in a stainless steel basket suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 900°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 30 minutes, while the gas was collected simultaneously.

[0107] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 900°C for 40 minutes.

[0108] Example 4

[0109] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:1, and dissolve them in deionized water, stirring until completely dissolved. Add citric acid in a molar ratio of 1.2 times the total number of metal cations and stir until completely dissolved. Place the solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 900℃ in air for 5 h to obtain the high-entropy oxide oxygen carrier Ni. 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 O4.

[0110] Ni was prepared according to an oxygen / carbon ratio of O / C = 0.5 (mass ratio 3.05:1). 0.6 Co 0.6 Fe 0.6 Mg 0.6 Al 0.6 After the high-entropy oxide oxygen carrier (O4) is thoroughly mixed with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.), it is placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas is then introduced into the closed fixed-bed reactor, and after heating to 900°C, the basket is quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 30 minutes while the gas is collected.

[0111] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 900°C for 40 minutes.

[0112] Example 5

[0113] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:2, and dissolve them in deionized water by stirring until completely dissolved. Add citric acid in an amount twice the total number of molar metal cations and stir until completely dissolved. Place the solution on a heated stirring table and evaporate at 80°C for 6 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 105°C for 24 h to obtain a dry gel. Calcinate the dry gel at 850°C in air for 6 h to obtain the high-entropy oxide oxygen carrier Ni. 0.5 Co 0.5 Fe 0.5 Mg 0.5 AlO4.

[0114] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 7:1). 0.5 Co 0.5 Fe 0.5 Mg 0.5 AlO4 high-entropy oxide oxygen carrier and a plastic mixture (PP, PE, PS, PET, and dechlorinated PVC in a mass ratio of 1:1:1:1:1, all manufactured by China Petrochemical Corporation Maoming Petrochemical Co., Ltd.) were mixed evenly and placed in a stainless steel basket, which was then suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 850°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 20 minutes, while the gas was collected simultaneously.

[0115] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 850°C for 30 minutes.

[0116] Example 6

[0117] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), magnesium nitrate hexahydrate (Mg(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 0.6:0.6:0.8:1:1, and dissolve them in deionized water by stirring until completely dissolved. Add citric acid in a molar ratio of 1.5 times the total number of metal cations and stir until completely dissolved. Place the above solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 950℃ for 5 h to obtain the high-entropy oxide oxygen carrier Ni. 0.45 Co 0.45 Fe 0.6 Mg 0.75 Al 0.75 O4.

[0118] Ni was prepared according to an oxygen-to-carbon ratio of O / C = 1 (mass ratio 5.7:1). 0.45 Co 0.45 Fe 0.6 Mg 0.75 Al 0.75 After the high-entropy oxide oxygen carrier (O4) is thoroughly mixed with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.), it is placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas is then introduced into the closed fixed-bed reactor, and after heating to 950°C, the basket is quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes while the gas is collected.

[0119] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 900°C for 30 minutes.

[0120] Example 7

[0121] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), zinc nitrate hexahydrate (Zn(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 0.4:0.3:1:0.3:1, and dissolve them in deionized water by stirring until completely dissolved. Add citric acid in a molar ratio of 1.5 times the total number of metal cations and stir until completely dissolved. Place the above solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 850℃ in air for 5 h to obtain a high-entropy oxide oxygen carrier Ni. 0.4 Co 0.3 FeZn 0.3 AlO4.

[0122] Ni was prepared according to an oxygen-to-carbon ratio of O / C = 1 (mass ratio 6.5:1). 0.4 Co 0.3 FeZn 0.3 AlO4 high-entropy oxide oxygen carrier and a plastic mixture (PP, PE, PS, PET, and dechlorinated PVC in a mass ratio of 1:1:1:1:1, all manufactured by China Petrochemical Corporation Maoming Petrochemical Co., Ltd.) were mixed evenly and placed in a stainless steel basket, which was then suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 850°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes, while the gas was collected simultaneously.

[0123] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 850°C for 30 minutes.

[0124] Example 8

[0125] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), zinc nitrate hexahydrate (Zn(NO3)2·6H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 1:1:1:1:1, and dissolve them in deionized water by stirring until completely dissolved. Add citric acid in a molar ratio of 1.5 times the total number of metal cations and stir until completely dissolved. Place the above solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 850℃ in air for 5 h to obtain the high-entropy oxide oxygen carrier Ni.0.6 Co 0.6 Fe 0.6 Zn 0.6 Al 0.6 O4.

[0126] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 6.8:1). 0.6 Co 0.6 Fe 0.6 Zn 0.6 Al 0.6 The high-entropy oxide oxygen carrier (O4) was mixed evenly with a plastic mixture (PP, PE, PS, PET, and dechlorinated PVC in a mass ratio of 1:1:1:1:1, all manufactured by China Petrochemical Corporation Maoming Petrochemical Co., Ltd.), and then placed in a stainless steel basket suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the sealed fixed-bed reactor, and after heating to 850°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes, while the gas was collected simultaneously.

[0127] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 850°C for 30 minutes.

[0128] Comparative Example 1

[0129] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and ferric nitrate nonahydrate (Fe(NO3)3·9H2O) in a molar ratio of 1:2, and dissolve them in deionized water with stirring until completely dissolved. Add citric acid in a molar ratio of 1.5 times the total number of metal cations and stir until completely dissolved. Place the above solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcine the dry gel at 850℃ for 5 h to obtain the oxide oxygen carrier NiFe2O4.

[0130] NiFe2O4 oxygen carrier was mixed with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.) at an oxygen / carbon ratio of O / C = 1 (mass ratio 4.17:1). The mixture was then placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 850°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes while the gas was collected.

[0131] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 850°C for 30 minutes.

[0132] Comparative Example 2

[0133] Fe3O4 oxygen carrier was mixed with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.) at an oxygen / carbon ratio of O / C = 1 (mass ratio 4.12:1). The mixture was then placed in a stainless steel basket and suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 850°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes while the gas was collected.

[0134] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 850°C for 30 minutes.

[0135] Comparative Example 3

[0136] Weigh nickel nitrate hexahydrate (Ni(NO3)2·6H2O), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), calcium nitrate tetrahydrate (Ca(NO3)2·4H2O), and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in a molar ratio of 0.4:0.3:1:0.3:1, and dissolve them in deionized water by stirring until completely dissolved. Add citric acid in a molar ratio of 1.5 times the total number of metal cations and stir until completely dissolved. Place the above solution on a heated stirring table and evaporate at 90℃ for 5 h to obtain a wet gel. Transfer the wet gel to an oven for drying at 110℃ for 10 h to obtain a dry gel. Calcinate the dry gel at 850℃ in air for 5 h to obtain a high-entropy oxide oxygen carrier Ni. 0.4 Co 0.3 FeCa 0.3 AlO4.

[0137] Ni was prepared according to an oxygen / carbon ratio of O / C = 1 (mass ratio 6.19:1). 0.4 Co 0.3 FeCa 0.3 AlO4 high-entropy oxide oxygen carrier was mixed evenly with polypropylene (PP, manufactured by Sinopec Maoming Petrochemical Co., Ltd.) and placed in a stainless steel basket, which was then suspended from the top of a fixed-bed reactor. Nitrogen gas was then introduced into the closed fixed-bed reactor, and after heating to 800°C, the basket was quickly lowered from the top onto the reactor bed, allowing the oxygen carrier to react with the waste plastic for 25 minutes, while the gas was collected simultaneously.

[0138] Then, the reaction atmosphere was switched to air, and the oxygen carrier after the reaction was regenerated at 800°C for 30 minutes.

[0139] <Tests and Evaluations>

[0140] The gases collected in the above examples and comparative examples were analyzed using a gas chromatograph (GC9720plus, Fuli) equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD), and the concentrations of each component (H2, CO2, CH4, CO, and N2) were measured. The N2 volumetric flow rate (…) was used to measure the concentrations of each component (H2, CO2, CH4, CO, and N2). Using (ml) as an internal standard, the molar number of each component was calculated based on the concentration of each component measured by GC using the following formula ( ):

[0141]

[0142] Among them, C i The molar concentrations of each component are... The molar concentration of N2 The molar volume of the gas at 25℃ and 101kPa is 22.4 L / mol.

[0143] The syngas yield was obtained for the gases collected in the above embodiments and comparative examples according to the following method. ):

[0144]

[0145] in, The number of moles of carbon monoxide. m is the number of moles of hydrogen gas. 塑料 This represents the mass of carbon in the plastic.

[0146] For the gases collected in the above embodiments and comparative examples, CO selectivity was obtained according to the following method ( ):

[0147]

[0148] in, The number of moles of carbon monoxide. Number of moles of carbon dioxide

[0149] For the gases collected in the above embodiments and comparative examples, the carbon conversion rate (X) was obtained according to the following method. c ):

[0150]

[0151] The number of moles of carbon monoxide. The number of moles of carbon dioxide. The number of moles of methane. The number of moles of ethane. The number of moles of ethylene. The number of moles of propane. The number of moles of propylene. The number of moles of acetylene. This represents the mass (g) of carbon in the plastic.

[0152] The syngas yield, CO selectivity, and carbon conversion of Examples 1-8 and Comparative Examples 1-3 are shown in Table 1.

[0153] Table 1

[0154]

[0155] As can be seen from Table 1, the syngas yield, CO selectivity and carbon conversion rate in Examples 1-8 were significantly higher than those in Comparative Examples 1-3.

[0156] The syngas yield and carbon conversion rate were determined using the method described above for the gases collected in each cycle of the experiment in Example 1. The results are as follows: Figure 1 As shown.

[0157] Depend on Figure 1 It can be seen that the syngas yield ranged from 82.82 to 75.41 mmol / g over 10 cycles. 塑料 The yield fluctuated between cycles, with the third cycle showing the lowest syngas yield relative to the first cycle, decreasing by 10.6 mmol / g. 塑料 Over the 10 cycles, CO selectivity fluctuated between 95.45% and 86.63%, with the lowest CO selectivity observed in the third cycle, which showed a decrease of 6.44% compared to the first cycle.

[0158] Industrial availability

[0159] The method of this invention can be widely used in industry for the treatment of waste plastics.

Claims

1. A method for producing syngas from plastic, characterized in that, Includes the following steps: This allows the plastic to undergo a chemical chain vaporization reaction by contacting high-entropy oxides. The plastic is selected from one or more of polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins; The high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.

8.

2. The method according to claim 1, characterized in that, The mass ratio of plastic to high-entropy oxide is 1:(1~10).

3. The method according to claim 1 or 2, characterized in that, The chemical looping gasification reaction is carried out at 700~1000℃.

4. The method according to claim 1 or 2, characterized in that, During the chemical looping gasification reaction, no oxygen, water vapor, or CO2 is added to the reaction system.

5. The method according to claim 1 or 2, characterized in that, The plastic is selected from one or more of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), and dechlorinated polyvinyl chloride (dechlorinated PVC).

6. The method according to claim 1 or 2, characterized in that, The method further includes the following steps: after the chemical looping gasification reaction is completed, the high-entropy oxide is regenerated to obtain the regenerated high-entropy oxide, wherein the regeneration of the high-entropy oxide is carried out in the presence of an oxidant; Preferably, the oxidant is one or more selected from air, water vapor, and carbon dioxide; Preferably, the regeneration of the high-entropy oxide is carried out at a temperature of 750~1050°C.

7. The method according to claim 5, characterized in that, The method further includes the following step: contacting the regenerated high-entropy oxide with a plastic to carry out a chemical chain gasification reaction, wherein the plastic is one or more selected from polyolefins, polystyrene, polyesters, and dehalogenated polyhalogenated olefins.

8. The use of high-entropy oxides in the production of syngas from plastics, characterized in that, The high-entropy oxide has the composition of Ni. a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.

8.

9. A high-entropy oxide, characterized in that, Composition is Ni a Co b Fe c M d Al e O x Where M is Mg or Zn, a is 0.2~1, b is 0.2~1, c is 0.2~1, d is 0.2~1, e is 0.2~2, a+b+c+d+e is 1~4, and x is 1.3~5.

8.

10. The method according to claim 1, the use according to claim 8, or the high-entropy oxide according to claim 9, characterized in that the ratio of a:b:c:d:e is (0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2):(0.8~1.2), preferably (0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1).

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