KR20230033796A - Apparatus and method of synthetic gas production from reforming of bio-oil by microwave plasma torch - Google Patents

Abstract

The present invention relates to the mass-production of synthetic gas by reforming bio-oil using an electromagnetic plasma torch, and more specifically, to a device and method for producing synthetic gas in large quantities by reforming, with high efficiency, bio-oil flowing into a reforming chamber with active particles, such as hydrogen atoms, oxygen atoms, hydrogen oxide molecule, and the like, and active particles self-generated within the high-temperature reforming chamber. Synthetic gas generated through reforming in the reforming chamber is mainly carbon monoxide and hydrogen and is a high-quality energy source that can efficiently produce electricity through fuel cells and the like and can also produce hydrogen through aqueous reaction and purification. In addition, synthetic gas produced from bio-oil is considered a carbon-neutral fuel and is excluded from carbon dioxide emissions, so no carbon tax is paid.

Description

Apparatus and method of synthetic gas production from reforming of bio-oil by microwave plasma torch}

The present invention relates to an apparatus and method for mass-producing syngas by reforming bio-oil using an electromagnetic wave plasma torch, and more particularly, to an apparatus and method for mass-producing syngas using an electromagnetic wave plasma torch. It relates to an apparatus and method for mass-producing syngas by reforming biocucumber using hydrogen molecules. Syngas from bio-oil is considered carbon-neutral and free from carbon dioxide emissions.

The Earth's space in which we live is limited, including the atmosphere. Nevertheless, as the global warming phenomenon accelerates due to our indiscriminate atmospheric layer pollution, the survival of mankind is threatened. As the industrial revolution began at the end of the 18th century, mankind sought a new energy source and eventually touched fossil fuels stored underground, and carbon dioxide generated thereby became the main culprit of global warming. When fossil fuels are used, the concentration of carbon dioxide in the atmospheric layer increases as much as it is used, and as a result, warming is accelerated, and all kinds of extreme weather events occur.

If we were smarter and could find a source of energy within the space we live in instead of fossil fuels, we would no longer do the stupid thing of releasing carbon dioxide into the atmosphere. Hydrocarbon compounds present on the surface are synthesized by carbon assimilation using sunlight by plants absorbing carbon dioxide in the atmosphere and water in the ground. These hydrocarbon compounds are commonly referred to as biofuels. Since carbon dioxide in the atmosphere is converted into biofuel and then returned to the atmospheric layer when used, no substantial increase in carbon dioxide occurs. It's just that carbon dioxide circulates in the space we live in, changing its form. So we should stop using fossil fuels and use biofuels. In other words, biofuels do not increase the amount of carbon dioxide in the atmosphere.

Humanity, suffering from extreme climate change, has made a resolution to reduce the additional emission of carbon dioxide to zero by 2050. Therefore, it is a policy to impose a carbon tax by introducing a system called carbon credits. As shown in Figure 1, carbon credits are rising steeply from 30 euros per ton of carbon dioxide at the end of last year to 49 euros at present, which is about $50 as of September 2021. The volume of one ton of carbon dioxide in the atmosphere is about 510 cubic meters. As can be seen from these figures, the toxicity of the atmospheric layer of carbon dioxide per ton is serious. So, with the introduction of the carbon tax, let's examine the numerical impact of this tax on our economic life.

Carbon, described by the chemical symbol C, is the main component of coal, and if coal is reformed into steam and converted into syngas of carbon monoxide and hydrogen and electricity is produced through a fuel cell, the chemical formula is C + H ₂ O → CO + H ₂ , the required reforming energy is 175.3 kJ per mole of carbon. And the energy contained in 1 mole of this syngas is 568.8 kJ. If the efficiency of the fuel cell is 55%, the electrical energy produced per 1 mole of carbon is 312.8 kJ, but the actual usable energy is 137.5 kJ after deducting the reforming energy. This is only 35% of the energy of one mole of carbon. Of course, in reality, it is not necessary to use expensive electricity for reforming energy of 175.3 kJ. This advantage will be explained in more detail later. So, to generate 1 MW of electricity using coal, (1000 kJ/137.5 kJ) = 7.27 moles of carbon per second. Since all of this carbon is converted into carbon dioxide, the amount of carbon dioxide produced per second is 320 g. So, the amount of carbon dioxide generated from this coal-fired power plant for one year is (320g) (3600) (24) (365)/10 ⁶ = 10,092 tons. This is currently $505,000 per year in carbon credits. Calculating this at the current exchange rate is 580 million won. If the electricity bill of 1kWh is 100 won, the electricity bill received from thermal power generation of 1 MW is 876 million won a year. Most of the electricity bills from these coal-fired power plants go to carbon tax. If the carbon credits reach $100, the electricity bill collected is not even enough to pay the carbon tax.

Then, what if city gas, which is described as CH ₄ , one of the fossil fuels, is reformed into water vapor, converted into syngas of carbon monoxide and hydrogen, and produced electricity through a fuel cell? In this case, the chemical reaction equation is CH ₄ + H ₂ O → CO + 3H ₂ and the required reforming energy is 250.1 kJ per mole of methane. And the energy contained in 1 mole of this syngas is 1140.4 kJ. If the efficiency of the fuel cell is 55%, the electrical energy produced per mol of methane is 627.2 kJ, but the actual usable energy is 377.1 kJ after deducting the reforming energy. The efficiency is 42%. To produce 1 MW of electricity from city gas, (1000 kJ/377.1 kJ) = 2.65 moles of methane flow per second. Since carbon in methane is converted into CO ₂ , the amount of CO ₂ produced per second is 116.7 g. The amount of carbon dioxide generated from city gas power generation for one year is (116.7g) (3600) (24) (365)/10 ⁶ = 3,680 tons. So the carbon tax is $184,000 a year. Compared to coal, it is much improved. However, considering the future increase in the carbon tax, it is also desirable not to use fossil fuels. Even if city gas is reformed with CO ₂ instead of steam, the result is almost the same.

In this situation, in terms of competitiveness, suppressing additional carbon dioxide generation by using biofuels has become directly related to the survival of a country or a company. So, by using biofuel instead of fossil fuel and converting biofuel into syngas as a way to use it more efficiently, we are trying to reduce carbon dioxide emissions by minimizing emissions of air pollutants and improving fuel efficiency.

The present invention is to meet the above-mentioned needs, and an object of the present invention is to produce syngas by reforming bio-oil. Syngas produced from bio-oil is carbon-neutral, free from carbon dioxide emissions.

In order to achieve this object, the present invention will first consider various bio-oils. One of the currently mass-produced bio-oils is palm oil extracted from cashews nut shells. It is produced a lot in subtropical regions such as Vietnam, and unrefined crude oil is currently known to be about 400 dollars per ton. Currently, palm oil is produced only in a small part of cashew nut shells collected in Vietnam, and the amount produced per day is reported to be about 4,000 tons.

When water is removed from food waste that we discharge every day and dried biomass (moisture 10%) is treated with a multi-stage drying carbonization device, polymer gas is generated between 250 and 400 degrees Celsius, which is condensed to produce bio-oil. Oil from food waste contains trace amounts of nitrogen. The liquefaction of waste plastic, which is an environmental pollutant, is also considered as bio-oil. A large amount of bio-oil can be extracted from waste rubber trees grown in the subtropics, and a large amount of bio-oil can be produced from rice hulls (rice mills) that are massively discharged in India. Considering all these things, it is possible to import bio-oil from subtropical regions and use it as biofuel without having to import crude oil (fossil fuel) from the Middle East.

In general, the flame temperature in an electromagnetic wave 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 a water vapor electromagnetic wave plasma flame. A large amount of oxygen atoms, hydrogen atoms and hydrogen oxide (OH) molecules are generated in the water vapor electromagnetic wave plasma torch flame. In a high-temperature reforming chamber, bio-oil molecules are reformed using these active particles to produce syngas composed of carbon monoxide and hydrogen molecules.

Korean Patent Registration No. 10-1166444 describes a carbon dioxide electromagnetic wave plasma torch. Oxygen atoms are generated in large quantities in the electromagnetic wave plasma torch flame made of carbon dioxide. The bio-oil molecules introduced into the high-temperature reforming chamber are attacked with oxygen atoms to decompose and reform to produce syngas of carbon monoxide and hydrogen.

Therefore, by injecting an electromagnetic wave plasma torch made using steam or carbon dioxide gas into a high-temperature reforming chamber, it is possible to very easily reform bio-oil molecules to produce a large amount of syngas of carbon monoxide and hydrogen.

As described above, the present invention increases energy efficiency by generating a large amount of active particles such as oxygen atoms, hydrogen atoms, and hydrogen oxide molecules using an electromagnetic torch, reforming bio-oil and converting it into high-quality energy.

The present invention improves global air quality by suppressing the emission of environmentally harmful substances such as fine dust by modifying bio-oil using active particles such as oxygen atoms, hydrogen atoms, and hydrogen oxide molecules generated in large quantities.

The present invention is expected to have a positive effect on global warming by reforming bio-oil and using energy more efficiently, thereby avoiding the problem of carbon dioxide emission.

1 is a schematic diagram of carbon credits per ton of carbon dioxide according to an embodiment of the present invention, and shows a steep rise in carbon credits compared to the end of last year.
Figure 2 is a block diagram of an apparatus and method for producing syngas by reforming bio-oil with an electromagnetic wave plasma torch according to an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to FIG. 2 . However, this is only an example and the present invention is not limited thereto.

In describing the present invention, if it is determined that a detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, 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 a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

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

2 is a block diagram of an apparatus and method for producing syngas by reforming bio-oil with an electromagnetic wave plasma torch according to an embodiment of the present invention.

As shown, the apparatus and method for producing syngas by reforming bio-oil with an electromagnetic wave plasma torch according to an embodiment of the present invention include a bio-oil supply unit 10, a reforming chamber 20, an electromagnetic wave torch system 30, It consists of an oxygen supply unit (40), a heat exchanger (50) and a syngas application (60).

The bio-oil supply unit 10 supplies somewhat purified bio-oil to the reforming chamber 20 in a liquid state.

The reforming chamber 20 maintains a high-temperature environment so that the purified bio-oil supplied from the bio-oil supply unit 10 can be spontaneously decomposed into low-molecular compounds while vaporizing in the high-temperature reforming chamber 20, and the electromagnetic torch system ( 30) creates an environment in which compounds decomposed into low molecules can be reformed by active particles generated in the inflowing water vapor or carbon dioxide. The inner wall of the reforming chamber 20 is made of a material that can withstand high temperatures for a long time (more than one month). For example, the inner surface may be coated with a heat-resistant ceramic material called HACT180 that can withstand up to 1800 degrees Celsius, and the next layer may use an insulating ceramic called INCT120. Graphite, which has a melting point of 3550 degrees Celsius, is also suitable as a heat resistor.

The electromagnetic wave torch system 30 generates a plasma torch flame using water vapor or carbon dioxide, and in this flame, a large amount of active particles such as oxygen atoms, hydrogen atoms, and hydrogen oxide (OH) molecules are generated. The torch flame is converted into a reforming chamber 20 supply to 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 transfers the high-temperature thermal energy of the torch to the reforming chamber 20. An electromagnetic wave oscillation semiconductor device that has recently been developed and matured may replace the magnetoron.

The electromagnetic wave torch system 30 uses expensive electrical energy to generate a torch flame and provides it to the reforming chamber 20 . Therefore, it may be economically difficult to provide all the energy required for reforming as electrical energy. In contrast, some of the energy-rich bio-oil can be burned to provide some of the reforming energy. In this context, the oxygen supplier 40 supplies oxygen to the reforming chamber 20 to partially oxidize the bio-oil, thereby providing some of the energy required for reforming.

The syngas obtained by reforming bio-oil in the reforming chamber 20 is mainly a mixed gas of hydrogen and carbon monoxide. When the syngas is discharged from the reforming chamber 20, the temperature generally approaches 1,000 degrees Celsius. However, since the following application processes are performed at a relatively low temperature, it may be necessary to cool the syngas temperature through the heat exchanger 50. In the process of cooling the synthesis gas, high-temperature steam is generated. This steam is used when generating a steam torch in the electromagnetic torch system 30.

The properly cooled syngas in the heat exchanger (50) is delivered to the syngas application (60) system. Syngas can be used in many fields. For example, electricity can be produced by injecting syngas of high-temperature hydrogen and carbon monoxide into a solid oxide fuel cell (SOFC). Water vapor and carbon dioxide are emitted from the fuel electrode of the fuel cell, and carbon dioxide is captured and It may also be used when generating a carbon dioxide torch in the electromagnetic wave torch system 30 . Alternatively, purified hydrogen may be produced from the cooled syngas through a water-shift reaction and a purification process (PSA: Pressure Swing Adsorption).

<Example 1>

As an example, we intend to reform palm oil extracted from Cashews nut shell produced in Vietnam. The elemental analysis of this palm oil sample is Cardanol content (C ₁₂ H _31-n : n = 0.2.4.6), and it is formed with a few miscellaneous things, and the energy content is 9,400 kcal/kg, which is a very good fuel. So, as a hypothetical compound that can best represent this condition, C ₁₅ H ₂₉ O ₃ seems suitable, and the molecular weight of this hypothetical compound is 257g, and the energy per mole is 2392kcal/mole, and the energy content is 9307kcal/kg. similar to the value The remaining 93 kcal may come from other impurities. A compound similar to this virtual compound can be found in the chemical table as C ₁₅ H ₃₀ O ₂ . The enthalpy of pentadecanoic acid is -811.7kJ/mole and the enthalpy of methyl tetradecanoste is -734.9kJ/mole. Therefore, the enthalpy of our virtual compound is assumed to be -800kJ/mole.

Then, in steam reforming, the carbon of this virtual compound is generally reformed to carbon monoxide, so the reforming equation is

C ₁₅ H ₂₉ O ₃ + 12H ₂ O → 15CO + 26.5H ₂ (1)

am. The enthalpy change for this reaction is H = 2044.1 kJ/mole. In other words, the virtual compound is reformed into carbon monoxide and hydrogen, and 2044.1 kJ of energy is required to reform 1 mole of the virtual compound.

For the purpose of reducing electricity consumption, it is possible to procure some of the energy required for reforming by oxidizing the virtual compound by introducing oxygen. Then the oxidation reaction equation is

C ₁₅ H ₂₉ O ₃ + 20.75 O ₂ → 15 CO ₂ + 14.5 H ₂ O (2)

and the enthalpy change of this reaction is H = - 8608.6 kJ/mole. It can be seen that a large amount of energy is generated when 1 mole of the virtual compound is oxidized. In Equation (1), reforming absorbs energy, and in Equation (2), oxidation generates energy. Therefore, we try to maintain the appropriateness of energy supply and demand through the oxidation reaction of an appropriate amount of virtual compounds. In order to find the value, x mole of the virtual compound is oxidized and equations (1) and (2) are combined. Then the overall reaction formula is

(1+x)C ₁₅ H ₂₉ O ₃ +(12-14.5x)H ₂ O+20.75xO ₂ →15CO+15xCO ₂ +26.5H ₂ (3)

and the enthalpy change of this reaction is

H = (2044.1 - 8608.6x) kJ/mole (4)

am.

The energy contained in the syngas on the right side of Equation 3 is 11818.7 kJ, and if the electricity conversion efficiency is 55%, the electricity production is 6500.3 kJ. To produce 1MW of electricity, 0.154 mole of (1+x)C ₁₅ H ₂₉ O ₃ virtual compound must be input per second. Multiplying this number by Equation (4) gives (314-1326x)kW. If 1 MW of electricity is produced, the appropriate size of the reformer is about 3 cubic meters, and the energy lost in the process of reforming is about 242 kW. So, the total energy input to the reformer is (556-1326x) kW. We want to put some of this energy into a steam torch, and we want the amount to be 90 kW. Then at 556-1326x = 90 x is x = 0.35. The molecular weight of the virtual compound C ₁₅ H ₂₉ O ₃ is 257 g. The amount of virtual compound injected per hour is (1.35) (257g/mole) (0.154mole/s) (3600s) = 192kg/hr.

The amount of oxygen required is (0.35) (25.75) (0.154) = 1.39 mole/s, which is 1864 liters of oxygen per minute. Meanwhile, the amount of water vapor is (12-0.35×14.5)(0.154) = 1.07 mole/s, which requires 69 kg of water vapor per hour. A technology that physically generates high-purity oxygen by continuously separating nitrogen and oxygen from the air using the PSA (Pressure Swing Adsorption) method using a zeolite adsorbent without using a chemical reaction has recently been realized. It has already been used in various fields requiring low-capacity oxygen, including ozone generation, and its usefulness has been proven. 150 kW of electricity will be used to generate 1864 liters of high-purity oxygen per minute. Then the electrical energy used for reforming is 90+150 = 240kW. So, the actual power that can be used outside after subtracting the 240 kW of autonomously used power becomes 760 kW. As shown in Equation 2, the energy of 1 mole of the virtual compound is 8608.6 kJ, and since (1.35) (0.154) mole is input per second, this input fuel is converted into electricity, which is 1.79 MW. Of these, only 760kW is used externally, so the power generation efficiency is 42%. It is similar to the city gas power efficiency described in the background of the invention. However, since bio-oil is used as fuel, the amount of carbon dioxide generated is considered zero, so there is no carbon tax.

<Example 2>

In this embodiment, a hypothetical compound (C ₁₅ H ₂₉ O ₃ ) is reformed with carbon dioxide to generate electricity. In carbon dioxide reforming, the reforming equation is

C ₁₅ H ₂₉ O ₃ + 12CO ₂ → 27CO + 14.5H ₂ (5)

am. The enthalpy change for this reaction is H = 2538.5 kJ/mole. In other words, the virtual compound is reformed into carbon monoxide and hydrogen, and 2538.5 kJ of energy is required to reform 1 mole of the virtual compound. If equation 2 is multiplied by x and combined with equation 5, the overall reaction equation for carbon dioxide reforming is

(1+x)C ₁₅ H ₂₉ O ₃ +(12-15x)CO ₂ +20.75xO ₂ →27CO+14.5H ₂ +14.5H ₂ O (6)

and the enthalpy change of this reaction is

H = (2538.5 - 8608.6x) kJ/mole (7)

am.

The energy contained in syngas on the right side of Equation 6 is 11785.1 kJ, and if the electricity conversion efficiency is 55%, the electricity production is 6418.8 kJ. To produce 1MW of electricity, 0.154 mole of (1+x)C ₁₅ H ₂₉ O ₃ virtual compound must be input per second. Multiplying this number by Equation (7) gives (391-1326x)kW. If 1 MW of electricity is produced, the size of the reformer suitable for it is about 3 cubic meters, and the energy lost in the process of reforming is about 242 kW. So the total energy input to the reformer is (633-1326x) kW. We want to put some of this energy into a CO ₂ torch, and we want the amount to be 90 kW. Then at 633-1326x = 90, x equals x = 0.4. The molecular weight of the virtual compound C ₁₅ H ₂₉ O ₃ is 257 g. The amount of virtual compound injected per hour is (1.4) (257g/mole) (0.154mole/s) (3600s) = 199kg/hr.

The amount of oxygen required is (0.4) (25.75) (0.154) = 1.59 mole/s, which is 2135 liters of oxygen per minute. On the other hand, the amount of _CO2 is (12-0.4×15)(0.154) = 0.92 mole/s, which requires 146kg of CO2 per hour. 150 kW of electricity will be used to generate 2135 liters of high-purity oxygen per minute. Then the electrical energy used for reforming is 90+150 = 240kW. So, the actual power that can be used outside after subtracting the 240 kW of autonomously used power becomes 760 kW. As shown in Equation 2, the energy of 1 mole of virtual compound is 8608.6 kJ, and (1.4) (0.154) mole per second is input, so if this input fuel is converted into electricity, it is 1.86 MW. Of these, only 760kW is used externally, so the power generation efficiency is 41%. Although the power generation by carbon dioxide reforming is slightly lower than that of steam reforming, the carbon dioxide torch continues to be mentioned because of the superiority of generating the carbon dioxide plasma torch.

Although the present invention has been described in detail through representative examples above, those skilled 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 not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

C: carbon
H ₂ O: water molecule
CO: carbon monoxide
H ₂ : hydrogen molecule
CH ₄ : methane molecule
_CO2 : carbon dioxide
SOFC: solid oxide fuel cell
C ₁₅ H ₂₉ O ₃ : Molecular formula of palm oil extracted from cashew nut shell
C ₁₅ H ₃₀ O ₂ : Pentadecanoic acid
H: enthalpy change
O ₂ : Oxygen molecule
ℓ: liter

Claims (9)

A bio-oil supply unit for supplying purified bio-oil in a liquid state to a reforming chamber in producing syngas by reforming bio-oil with an electromagnetic wave plasma torch;
a reforming chamber maintaining a high-temperature environment suitable for reforming the liquid bio-oil supplied from the bio-oil supply unit into steam 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 supplier supplying oxygen necessary for burning a portion of the bio-oil to the reforming chamber to provide a portion of the reforming energy;
a heat exchanger for cooling the reformed syngas discharged from the reforming chamber to an appropriate temperature; and
A device for producing syngas by reforming bio-oil with an electromagnetic wave plasma torch, including a syngas application part for applying the cooled syngas
According to claim 1,
The suitable high-temperature environment means an environment in which the internal temperature of the reforming chamber is maintained at 1,000 degrees Celsius or more, a device for producing syngas by reforming bio-oil with an electromagnetic wave plasma torch
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. Producing syngas by reforming bio-oil with an electromagnetic plasma torch device to
According to claim 1,
The electronic wave torch system is a system that supplies active particles and energy required for the reforming to the reforming chamber as 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 synthesis gas by reforming bio-oil with an electromagnetic wave plasma torch, characterized in that it is configured and the electromagnetic waves generated from the magnetron generate a torch flame in the discharge tube
According to claim 1,
The cooling to the appropriate temperature is a device for producing synthesis gas by reforming bio-oil with an electromagnetic wave plasma torch, characterized in that cooling to a temperature suitable for the synthesis gas application part
According to claim 4,
The magnetron is a device for producing synthesis gas by reforming bio-oil with an electromagnetic wave plasma torch, which may be replaced by an electromagnetic wave oscillation semiconductor device
Injecting the purified bio-oil in a liquid state into the reforming chamber;
Injecting water vapor or carbon dioxide gas into the electromagnetic torch system;
generating a torch flame in a discharge tube in the electromagnetic wave torch system;
generating a large amount of active particles in the flame of the torch;
Producing syngas by reforming bio-oil using the large amount of active particles; and
A method of producing syngas by reforming bio-oil, which consists of cooling the high-temperature syngas, with an electromagnetic wave plasma torch
According to claim 7,
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. Method for producing hydrogen by reforming bio-oil with an electromagnetic wave plasma torch
According to claim 7,
A method of producing syngas by reforming bio-oil with an electromagnetic wave plasma torch in the process of collecting high-temperature thermal energy to increase overall system energy efficiency in the process of cooling syngas.

Images