KR20220116380A - Apparatus and method of hydrogen production from reforming of plastic waste by microwave plasma torch - Google Patents

Abstract

The present invention relates to an apparatus and method for mass-producing hydrogen by reforming waste plastic using an electromagnetic wave plasma torch, and more specifically to the apparatus and method for mass-producing hydrogen by reforming a waste plastic compound in a high temperature reforming chamber with high efficiency by injecting water vapor or carbon dioxide into an electromagnetic plasma torch system and using active particles, which can be generated in a torch flame, such as oxygen atoms, hydrogen oxide molecules, hydrogen atoms, and carbon monoxide molecules. In addition, synthesis gas produced by reforming in the reforming chamber is mainly carbon monoxide and hydrogen, wherein carbon monoxide is converted into hydrogen through a water gas reaction, and hydrogen is purified through a pressure swing adsorption (PSA) process. Accordingly, waste vinyl waste plastic, which is the most lethal to the global environment, is removed and hydrogen, the most environmentally friendly energy source, is produced.

Description

Apparatus and method of hydrogen production from reforming of plastic waste by microwave plasma torch}

The present invention relates to an apparatus and method for mass production of hydrogen by reforming waste plastics using an electromagnetic plasma torch, and more particularly, oxygen atoms, hydrogen oxide molecules, hydrogen atoms, carbon monoxide molecules, etc. It relates to an apparatus and method for mass production of hydrogen by reforming waste plastic using

The Earth we live in is limited in resources and space. In particular, household waste is causing enormous environmental problems on the earth. We humans produce more than 2 billion tons of household waste every year. This problem is expected to get worse. It is said that whales in the ocean are dying at the same time as they pollute land and sea by indiscriminately using various kinds of plastics and plastics for convenience. Most of the waste plastics are made of polyethylene, but PVC (Polyvinyl Chloride) is also mixed in them.

As shown in FIG. 1 , ethylene is a compound in which two hydrogen atoms are attached to carbon atoms having double bonds. Polyethylene is a complex compound in which countless ethylene molecules are connected. In vinyl chloride, as shown in FIG. 1 , one hydrogen atom in an ethylene molecule is substituted with a chlorine atom. PVC is a compound in which many of these vinyl chloride molecules are also connected and combined. Vinyl chloride is flammable, toxic and known to cause cancer. It is said that 13 million tons of vinyl chloride are synthesized annually. However, when these dangerous substances are combined with polyvinyl chloride and transformed into polyvinyl chloride, they are considered non-toxic and are scattered around us, such as building materials, and these are returned to waste plastic and pollute the earth. We intend to mass-produce the most environmentally friendly hydrogen by reforming waste plastic pollutants, which are the most painfully destroying the global environment, with an electromagnetic plasma torch. In other words, while removing waste plastic waste, which is the main pollutant of the global environment, we want to produce hydrogen, which is essential for us.

The present invention is to satisfy the above-mentioned needs, and an object of the present invention is to produce hydrogen by reforming waste plastics at a high temperature.

In order to achieve this object, the present invention first needs to compare the structure of polyethylene and the structure of diesel in FIG. 2 as shown in FIG. 1 . Its structure is similar, but polyethylene is a very long complex. When polyethylene melts into a liquid in a high-temperature reforming chamber and begins to decompose, it will resemble diesel molecules. Light oil (C ₁₂ H ₂₆ ) splits into small molecules at high temperatures (1200 degrees Celsius). For example, C ₁₂ H ₂₆ → C ₅ H ₁₁ + C ₇ H ₁₅ , C ₁₂ H ₂₆ → C ₄ H ₉ + C ₈ H ₁₇ , C ₁₂ H ₂₆ → C ₃ H ₇ + C ₉ H ₁₉ , and C ₁₂ H ₂₆ → C ₂ H ₅ + C ₁₀ H ₂₁ , etc., is split in one millionth of a second. So what about the molecules that are formed by decomposition of diesel? For example, the molecule C ₁₀ H ₂₁ decomposes into C ₁₀ H ₂₁ → C ₂ H ₄ + C ₈ H ₁₇ in 100 millionths of a second. In this pattern, it is very quickly decomposed into small molecules, resulting in a mixture of CH ₄ , C ₂ H ₆ , C ₂ H ₄ , C ₂ H ₂ , CH ₃ , H and the like. It is self-evident that polyethylene molecules are also split into low molecules in the high-temperature reforming chamber, just as gas oil molecules are split into low molecules in the high-temperature reforming chamber. Hydrogen can be easily produced by reforming the already low molecular weight hydrocarbon compounds into active particles generated from the torch by injecting water vapor or carbon dioxide required for reforming at a high temperature through an electromagnetic plasma torch.

In general, the flame temperature in the electromagnetic plasma torch is very high. The center is 6,500 degrees Celsius, but the temperature drops towards the end of the flame. Korean Patent Registration No. 10-0864695 describes the properties of vapor electromagnetic wave plasma flame. 3 is a graph showing the density of oxygen (n _O ) hydrogen (n _H ) atoms and hydrogen oxide (OH) molecules (n _OH ) as the temperature T _g of the flame of the steam torch. Here, T _g means the absolute temperature. It can be seen that the density of oxygen atoms in the flame at an absolute temperature of 2000K is 10 ¹⁴ /cm ³ . When this amount of oxygen atoms attack the low molecular weight hydrocarbon compound, reformation can occur easily.

Korean Patent Registration No. 10-1166444 describes a carbon dioxide electromagnetic wave plasma torch. The generation of oxygen atoms in the electromagnetic plasma torch flame made of carbon dioxide can be observed in FIG. 4 . At an absolute temperature of 2000 K, the density of oxygen atoms (n _O ) is very high as 5×10 ¹⁷ /cm ³ , and this density of oxygen atoms is formed in 1/100,000th of a second. Therefore, by injecting an electromagnetic plasma torch made using water vapor or carbon dioxide gas into a high-temperature reforming chamber, it is very easy to reform low molecular weight polyethylene waste plastic and mass-produce syngas.

So what about polyvinyl chloride? As shown in Figure 1, the structure of polyvinyl chloride is also similar to that of a light oil molecule, but only vinyl chloride molecules form a complex. will decompose In particular, it decomposes while releasing hydrogen chloride (HCl). For example, a vinyl chloride molecule decomposes itself into acetylene (C ₂ H ₂ ) and hydrogen chloride according to the reaction scheme C ₂ H ₃ Cl → C ₂ H ₂ + HCl, and the decomposition constant is shown in FIG. 5 . It decomposes within 1/1000 of a second even at an absolute temperature of 1400K in the reforming chamber. And acetylene is easily decomposed by the oxygen atom mentioned above.

As described above, the present invention provides a basis for improving the global environment by generating a large amount of active particles such as oxygen atoms, hydrogen atoms, hydrogen oxide molecules, carbon monoxide molecules, and the like, and using them for reforming waste plastics.

The present invention removes waste plastic polluting the earth by using active particles such as oxygen atoms, hydrogen atoms, hydrogen oxide molecules, etc. generated in large quantities.

The present invention produces hydrogen, the most environmentally friendly source of high-quality energy by reforming waste plastic pollutants that are destroying the global environment.

The present invention provides conditions for efficiently reforming general hydrocarbon compounds including biogas.

1 is a schematic diagram showing chemical molecular formulas such as ethylene polyethylene vinyl chloride (Vinyl Chloride) polyvinyl chloride according to an embodiment of the present invention;
Figure 2 is a schematic diagram showing the chemical molecular formula of light oil (Diesel) according to an embodiment of the present invention
3 is a graph showing the density of oxygen atoms, hydrogen atoms, and hydrogen oxide molecules in the flame of a steam plasma torch according to an embodiment of the present invention as a function of the temperature T _g of the flame.
4 is a graph showing the density of oxygen atoms (n _O ) and the time it takes to form the density (t _half ) as a function of the temperature T _g of the flame area in a carbon dioxide plasma torch flame according to an embodiment of the present invention.
5 is a graph showing the decomposition constant of vinyl chloride itself decomposed in the reforming chamber at a high temperature according to an embodiment of the present invention as a function of the temperature T of the reforming chamber.
6 is a block diagram of an apparatus and method for producing hydrogen by reforming waste plastic with an electromagnetic plasma torch according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is merely an example and the present invention is not limited thereto.

In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. And, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or operator. Therefore, the definition should be made based on the content throughout this specification.

The technical spirit of the present invention is determined by the claims, and the following examples are only one means for effectively explaining the technical spirit of the present invention to those of ordinary skill in the art to which the present invention belongs.

6 is a block diagram of an apparatus and method for producing hydrogen by reforming waste plastic with an electromagnetic plasma torch according to an embodiment of the present invention.

As shown, an apparatus and method for producing hydrogen by reforming waste plastics with an electromagnetic plasma torch according to an embodiment of the present invention include a waste plastic preprocessor 10, a reforming chamber 20, an electromagnetic torch system 30, It consists of an oxygen supply unit 40 , a heat exchanger 50 , a water gas reaction 60 and a PSA 70 .

The waste plastic preprocessor 10 pulverizes various incoming waste plastics or vinyl into small particles (pellets) and supplies them to the reforming chamber 20, or heats the waste plastic particles to 250 degrees Celsius to form a liquid reforming chamber ( 20) is supplied.

The reforming chamber 20 maintains a high temperature environment so that the waste plastic material supplied from the waste plastic preprocessor 10 is maintained at a high temperature while the waste plastic material is reformed by water vapor or carbon dioxide introduced from the electromagnetic torch system 30 . The inner wall of the reforming chamber 20 is made of a material that can withstand a high temperature for a long time (one month or more). For example, the inner surface is coated with a heat-resistant ceramic material called HACT180 that can withstand up to 1800 degrees Celsius, and the next layer is a thermal insulation ceramic called INCT120. Graphite, which has a melting point of 3550 degrees Celsius, is also suitable as a heat resistor.

The electromagnetic torch system 30 generates a plasma torch flame using water vapor or carbon dioxide, and converts the torch flame in which a large amount of active particles such as oxygen atoms, hydrogen atoms, hydrogen oxide (OH) molecules, and carbon monoxide molecules are generated in the flame to the reforming chamber ( 20) is supplied. The electromagnetic wave torch system 30 is composed of a magnetron, a power supply unit, a circulator, a directional coupler, a stub tuner, a waveguide, and a discharge tube. , and also transfers the high-temperature thermal energy contained in the torch to the reforming chamber 20 .

The electromagnetic wave torch system 30 generates a torch flame using expensive electric energy and provides it to the reforming chamber 20 . Therefore, there may be economic difficulties in providing all the energy required for reforming with the electromagnetic torch. Conversely, it is also possible to burn some of the energy-rich waste plastic material and provide it with some of the reforming energy. In this context, the oxygen supply unit 40 supplies oxygen to the reforming chamber 20 to partially oxidize the waste plastic material, thereby procuring a portion of energy required for reforming.

The waste plastic material is reformed into syngas in the reforming chamber 20. When the syngas mainly mixed with hydrogen and carbon monoxide is discharged from the reforming chamber 20, the temperature generally approaches 1,000 degrees Celsius. However, since the following processes are carried out at a low temperature, the syngas temperature must be cooled through the heat exchanger 50 . Although most of the waste plastic is polyethylene, a small amount of hydrogen chloride generated by the decomposition of polyvinyl chloride contained in some may be included in the syngas. So, hydrogen chloride is removed in the process through the heat exchanger 50 . In the process of cooling the syngas, high-temperature steam is generated, and this steam is used when generating a steam torch in the electromagnetic wave torch system 30 .

Syngas sufficiently cooled in the heat exchanger 50 is converted into carbon monoxide and hydrogen while passing through the water gas reaction (60) process. The water gas reaction 60 also uses a portion of water vapor. Water gas reaction is carried out at 200 degrees Celsius or less. The synthesis gas after the water gas reaction (60) is a mixed gas of hydrogen and carbon dioxide. This synthesis gas is finally separated from carbon dioxide and hydrogen through a purification process called PSA (70). Part of the carbon dioxide generated here is used to generate a carbon dioxide plasma torch in the electromagnetic torch system 30 . PSA (Pressure Swing Adsorption) referred to here refers to the gas purification process.

<Example 1>

In one embodiment, polyethylene is modified with steam plasma. Polyethylene, the main component of plastics, is a complex in which numerous ethylene molecules are bound. So, for convenience of analysis, we will assume that it is a compound with N ethylene molecules attached. So, the chemical formula of this hypothetical molecule is (C ₂ H ₄ ) _N. The enthalpy of this molecule is assumed to be -E kJ/mole. When reforming this compound with a steam torch, the comprehensive chemical reaction is

(C ₂ H ₄ ) _N + 2NH ₂ O → 2NCO + 4NH ₂

As , the enthalpy change of this reaction is DH = (262.6N+E) kJ/mole, which is an endothermic reaction, and the molecular weight of this compound is 28Ng/mole. In the above chemical equation, N means an integer number, not a nitrogen atom. Here, the enthalpies of water vapor and carbon monoxide were calculated to be -241.8 kJ/mole and -110.5 kJ/mole, respectively. Since carbon monoxide is converted into hydrogen by water gas reaction (60) CO + H ₂ O → CO ₂ + H ₂ , 6N moles of hydrogen are generated by reforming 1 mole of the hypothetical compound.

We assume that we produce 300 cubic meters of hydrogen per hour. Then, 2232/N moles of the virtual compound per hour are introduced into the reforming chamber 20 . This corresponds to 0.62/N mole/s. Therefore, the energy required for reforming is (0.62/N)(262.6N+E)=(162.8+0.62E/N) kW. The reforming chamber 20 of this size has an internal capacity of about 1.8 cubic meters, and the energy lost in the reforming process is about 140 kW. Most of the energy loss is the energy that syngas carries, and some of it is lost through conduction and the like. So, the energy required for the reforming process is (302.8+0.62E/N)kW.

The energy of this hypothetical compound is calculated from the oxidation reaction (C ₂ H ₄ ) _N + 3NO ₂ → 2NCO ₂ + 2NH ₂ O, and the change in enthalpy of this oxidation reaction is DH = -(1270.6NE)kJ/mole. So 0.62/N mole/s of waste polyethylene material per second is required, so the energy contained in waste polyethylene is (1270.6NE)(0.62/N) = (787.8-0.62E/N)kW. Therefore, the total energy input to the reforming chamber 20 is (302.8+0.62E/N)+(787.8-0.62E/N)=1090.6kW. It is noteworthy here that the total energy input is independent of the number N and the enthalpy of the hypothetical compound -EkJ/mole. That is, it depends only on the energy of the carbon and hydrogen atoms. The hydrogen energy produced is 300 rubes when calculated as the enthalpy of water generated by the reaction of H ₂ + (1/2)O ₂ → H ₂ O -285.8kJ/mole (High Value: this value is generally adopted as the gasifier efficiency) The hydrogen energy of is 1063.2 kW. So the reforming energy efficiency is η = 1063.2/1090.6 = 0.97. The reason why the reforming energy efficiency is so high is that high-temperature steam generated in the heat exchanger 50 is injected into the electromagnetic wave torch system 30 . However, since about 60 kW of energy is required in the PSA 70 and the like to produce 300 cubic meters of hydrogen per hour, the total energy input is 1150.6 kWrk, and the overall energy efficiency is η = 1063.2/1150.6 = 0.92. The amount of waste polyethylene input per hour is (28Ng/mole)(2232mole/N)=62.5kg, which is also independent of the number N.

<Example 2>

In this embodiment, polyethylene is modified with carbon dioxide plasma. At this time, when reforming the polyethylene hypothetical compound with a carbon dioxide torch, the comprehensive chemical reaction is

(C ₂ H ₄ ) _N + 2NCO ₂ → 4NCO + 2NH ₂

and the enthalpy change of this reaction is DH = (345N+E) kJ/mole, which is an endothermic reaction. Here, the enthalpy of carbon dioxide was calculated to be -393.5 kJ/mole. Even in this modification, 6N moles of hydrogen are generated per mole of the hypothetical compound. In this case, the reforming energy required to produce 300 cubic meters of hydrogen per hour is (0.62/N)(345N+E)=(214+0.62E/N) kW. Attached here is an energy loss of 140 kW in the reforming chamber 20 . The total energy being input to the reforming chamber 20 is (354+0.62E/N)+(787.8-0.62E/N)=1141.7kW. If 60 kW of power used outside the reforming chamber 20 is added to this, the total energy input is 1201.7 kW, and the energy efficiency is η = 1063.2/1201.7 = 0.88. Carbon dioxide torches are slightly less energy efficient than steam torches. Nevertheless, it is easier to generate a carbon dioxide torch than a steam torch, and when comparing FIGS. 3 and 4, there is an advantage that the generation of oxygen atoms in the carbon dioxide torch is much higher than that of the steam torch.

<Example 3>

In this example, the reforming of polyvinyl chloride with a steam plasma torch will be carried out. In this case, the molecular formula of the hypothetical compound is (C ₂ H ₃ Cl) _N . When reforming this compound with a steam torch, the comprehensive chemical reaction is

(C ₂ H ₃ Cl) _N + 2NH ₂ O → 2NCO + 3NH ₂ + NHCl

As , the enthalpy change of this reaction is DH = (170.3N+E) kJ/mole, which is an endothermic reaction, and the molecular weight of this compound is 62.5Ng/mole. In this case, the amount of hydrogen generated per mole of the polyvinyl chloride virtual compound is 5N moles. The hypothetical number of moles of polyvinyl chloride required to produce 300 cubic meters of hydrogen per hour is 2678.6 moles, which corresponds to 0.74/N mole/s. So the required reforming energy is (126.7+E/N)kW. In the case of polyvinyl chloride, since the internal volume of the reforming chamber 20 must be increased by 20%, the energy loss through reforming also increases by 20% to 168kW. The energy to be input to the reforming chamber 20 is (294.7+E/N)kW.

The energy of this hypothetical polyvinyl chloride compound is calculated from the oxidation reaction (C ₂ H ₃ Cl) _N + 3NO ₂ → 2NCO ₂ + NH ₂ O + NHClO, and the change in enthalpy of this oxidation reaction is DH = -(1105.6NE)kJ /mole. Here, the enthalpy of hypochlorous acid (HClO) was calculated to be -76.8 kJ/mole. The energy input to polyvinyl chloride is (818-E/N)kW. Therefore, the energy input to the reforming chamber 20 including the reforming material is 1113 kW. If 60kW of energy required outside the reforming chamber 20 is added to this, the total is 1173kW. Therefore, the energy efficiency is η = 1063.2/1173 = 0.91. The polyvinyl chloride required to produce 300 cubic meters of hydrogen per hour is 167 kg. In practical circumstances, Example 1 would be realistic because most of the waste plastic is polyethylene and some polyvinyl chloride is introduced. However, even if a little polyvinyl chloride is mixed in the waste plastic, the generated hydrogen chloride must be removed from the heat exchanger (50).

Although the present invention has been described in detail through representative embodiments above, those of ordinary skill in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. will understand

Therefore, the scope of the present invention should not be limited to the described embodiments, and should be defined by the claims described below as well as the claims and equivalents.

PSA (Pressure Swing Adsorption): Tablets
PVC (Polyvinyl Chloride): Polyvinyl Chloride
Vinyl Chloride: Vinyl Chloride
Ethylene: Ethylene
Polyethylene: Polyethylene
C ₁₂ H ₂₆ : light oil
C ₁₂ H ₂₆ → C ₅ H ₁₁ + C ₇ H ₁₅ , C ₁₂ H ₂₆ → C ₄ H ₉ + C ₈ H ₁₇ , C ₁₂ H ₂₆ → C ₃ H ₇ + C ₉ H ₁₉ , C ₁₂ H ₂₆ → C ₂ H ₅ + C ₁₀ H ₂₁ : Reaction formulas for decomposition of light oil
C ₁₀ H ₂₁ → C ₂ H ₄ + C ₈ H ₁₇ : Reaction formula for decomposition of compound C ₁₀ H ₂₁
CH ₄ : Methane
C ₂ H ₆ : ethane
C ₂ H ₄ : Ethylene
C ₂ H ₂ : Acetylene
CH ₃ : ethyl
H: hydrogen atom
n _O : density of oxygen atoms
n _H : density of hydrogen atoms
n _OH : hydrogen oxide molecular density
OH: hydrogen oxide
T _g : plasma torch flame temperature
K: absolute temperature
HCl: hydrogen chloride
C ₂ H ₃ Cl: vinyl chloride
Diesel: via
t _half : Oxygen atomic density formation time
T: internal temperature of reforming chamber
Pellet: Particles
HACT180: heat-resistant ceramic
INCT120: Thermal Insulation Ceramic
(C ₂ H ₄ ) _N : ethylene molecular complex
N: the number of ethylene molecules in the ethylene molecular complex
-E: Enthalpy of the complex
H ₂ : hydrogen molecule
DH: Enthalpy change
CO: carbon monoxide
H ₂ O: water
CO ₂ : carbon dioxide
O ₂ : oxygen molecule
η : energy efficiency
(C ₂ H ₃ Cl) _N : vinyl chloride molecular complex
HClO: hypochlorous acid
k : decomposition constant of vinyl chloride molecule

Claims (8)

a waste plastic preprocessor that pulverizes waste plastics or vinyl into small particles and supplies them to a reforming chamber in the production of hydrogen by reforming waste plastics with an electromagnetic plasma torch;
a reforming chamber for maintaining a high-temperature environment suitable for reforming the waste plastic material supplied from the plastic preprocessor into water vapor or carbon dioxide;
an electromagnetic wave torch system for generating a plasma torch flame using water vapor or carbon dioxide and supplying the torch flame containing a large amount of active particles to the reforming chamber;
an oxygen supply for supplying the reforming chamber with oxygen necessary for partial combustion of the waste plastic material to provide a portion of reforming energy;
a heat exchanger for cooling the reformed syngas discharged from the reforming chamber to a high temperature to a low temperature;
a water gas reactor for converting carbon monoxide mixed in the cooled synthesis gas into carbon dioxide and hydrogen; and
A device for producing hydrogen by reforming waste plastic with an electromagnetic plasma torch, including a PSA purification device that finally separates hydrogen and carbon dioxide mixed in the synthesis gas through the water gas reaction process
According to claim 1,
The suitable high-temperature environment is an apparatus for reforming waste plastics with an electromagnetic wave plasma torch to produce hydrogen so that the temperature inside the reforming chamber is maintained at 1,200 degrees Celsius or more
According to claim 1,
The active particles mean oxygen atoms, hydrogen atoms, and hydrogen oxide molecules in the case of a steam torch flame, and oxygen atoms and carbon monoxide molecules in the case of a carbon dioxide torch flame. Reforming waste plastic with an electromagnetic plasma torch to produce hydrogen Device
According to claim 1,
The electromagnetic wave torch system is a system for supplying active particles and energy required for the reforming to the reforming chamber with a torch flame, and includes a magnetron, a power supply unit, a circulator, a directional coupler, a stub tuner, a waveguide, and a discharge tube. A device for producing hydrogen by reforming waste plastic into an electromagnetic plasma torch, characterized in that the electromagnetic wave generated from the magnetron generates a torch flame in the discharge tube
According to claim 1,
The cooling to the low temperature is a device for producing hydrogen by reforming waste plastic with an electromagnetic wave plasma torch, characterized in that cooling to 200 degrees Celsius or less
The process of crushing waste plastics or vinyl into small particles and injecting them into the reforming chamber;
The process of injecting water vapor or carbon dioxide molecules into the electromagnetic torch system;
generating a torch flame in the discharge tube in the electromagnetic wave torch system;
generating a large amount of active particles in the torch flame;
producing syngas by reforming the waste plastic material using the large amount of active particles;
The process of cooling the high-temperature syngas;
converting carbon monoxide mixed in the synthesis gas into carbon dioxide and hydrogen; and
A method of producing hydrogen by reforming waste plastics that are finally separated and refining hydrogen and carbon dioxide with an electromagnetic plasma torch
7. The method of claim 6,
The large amount of active particles means oxygen atoms, hydrogen atoms, and hydrogen oxide molecules in the case of a steam torch flame, and oxygen atoms and carbon monoxide molecules in the case of a carbon dioxide torch flame. A method of reforming waste plastics with an electromagnetic plasma torch to produce hydrogen
7. The method of claim 6,
A method of producing hydrogen by reforming waste plastic with an electromagnetic wave plasma torch, which consists of a process of collecting high-temperature thermal energy to increase overall system energy efficiency in the process of cooling syngas

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