KR100537658B1 - Plasma Reforming Method and Apparatus for Biogas - Google Patents

Abstract

The present invention is a synthetic gas that can be utilized as raw materials for chemical, electronic and semiconductor using biogas and gas fuel such as natural gas or LPG, for power generation using fuel cells, and as clean alternative energy for fossil fuels. The present invention relates to a plasma reforming method and apparatus for biogas for hydrogen production.

The plasma reforming method of the biogas of the present invention includes a biogas introduction step (S10) of supplying various biogases to the plasma reforming reactor (4) via the gas introduction unit (14); Steam supply step (S20) for supplying steam to the plasma reforming reactor (4) from the steam generator (8); A plasma reforming step (S30) of heating the biogas supplied from the gas introducing unit 14 by a heating device 46 and then reforming the biogas supplied by the low temperature plasma or the high temperature plasma generated in the plasma reforming reactor (4); And a syngas storage step (S40) for separating water from the syngas generated in the plasma reforming reactor (4) by the gas-liquid separator (9) and storing it in the storage tank (10).

Therefore, according to the present invention, by converting the biogas into a high-quality synthetic gas rather than directly burning it, it can be recycled as a synthetic gas, and can safely treat volatile organic compounds of the biogas. The amount of greenhouse gas generated can be greatly reduced.

Description

Plasma Reforming Method and Apparatus for Biogas

The present invention relates to a plasma reforming method for a variety of biogas, and more specifically, using a biogas generated in an anaerobic reaction tank or landfill during the food waste treatment and wastewater treatment process, using a gas, such as natural gas or LPG, A method and apparatus for plasma reforming of biogas for syngas (also referred to as SynGas) / hydrogen production, which can be used as raw materials for electronics and semiconductors, for power generation using fuel cells, and as clean alternative energy for fossil fuels .

Although the number of energy per person is increasing rapidly due to the development of industry and the development of scientific and civilization, the development of alternative energy is urgent due to the problem of energy depletion due to the limitation of fossil fuel. Currently, research on the development of various alternative energies is being conducted. Among them, interest in the use of alternative energy for biogas generated from landfills, wastewater treatment plants, and methane-producing anaerobic fermenters of food waste is gradually increasing. However, in the case of such a biogas, low calorific value during direct combustion decreases in combustibility, and ammonia (NH ₃ ) There was a problem that a large amount of air pollutants are generated by including impurities such as. In addition, there is another problem that the constant heat supply is difficult due to problems such as boiler fluctuation when using the waste heat by direct combustion because the composition of the gas is not uniform.

Therefore, there has been a demand for a technology that can significantly reduce odors and greenhouse gas emissions while treating volatile organic compounds by recycling them into high-quality synthetic gas (SynGas) rather than directly burning them. as is the number of ways, such as the proposed partial oxidation method (partial oxidation), CO ₂ reforming (CO ₂ reforming), steam reforming (steam reforming). Among them, the steam reforming method is most used at present due to advantages such as gas throughput and hydrogen production yield, but high temperature and pressure are required, and a catalyst is used to increase the hydrogen conversion rate.

The present invention has been proposed to solve the problems of the conventional reforming method as described above, using the simulated biogas (simulated biogas) factors affecting the biogas conversion rate pulse frequency, biogas component ratio, water vapor flow rate ratio, The purpose of this study is to convert biogas into synthetic gas, which is a high quality low pollution alternative energy, by identifying the reforming characteristics according to gas flow rate and pulse power change.

In order to achieve the above object, the present invention provides a biogas introduction step of supplying various biogases to a plasma reforming reactor through a gas introduction unit; Steam supply step of supplying steam from the steam generator to the plasma reforming reactor; A plasma reforming step of heating the biogas supplied from the gas introduction unit with a heating device and then reforming the biogas supplied by the low temperature plasma or the high temperature plasma generated in the plasma reforming reactor; And a syngas storage step of separating water from the syngas generated in the plasma reforming reactor by a gas-liquid separator and storing the syngas in a storage tank.

The present invention also provides a gas introduction unit for compressing and storing various biogas, a plasma reforming reactor for preheating the biogas supplied from the gas introduction unit with a heating device, and reforming by plasma generated therein, and supplying steam to the plasma reforming reactor. The present invention provides a plasma reforming apparatus for a biogas comprising a steam generator and a syngas storage unit for separating and storing moisture from syngas generated in a plasma reforming reactor.

Now, a plasma reforming method and apparatus for biogas for syngas / hydrogen production according to the present invention will be described in detail with reference to the accompanying drawings.

First, the plasma reforming apparatus of the present invention includes a gas introducing unit 14, a plasma reforming reactor 4, a steam generator 8, and a syngas storage unit 15, as shown schematically in FIG.

Here, the gas introduction part 14 is comprised from the compressor 2 connected with the anaerobic reactor 1, and the gas storage tank 3 which stores the biogas compressed by this compressor 2 as shown.

The plasma reforming reactor 4 connected to the gas storage tank 3 of the gas introduction unit 14 is configured to reform the biogas supplied from the gas introduction unit 14 by the plasma generated therein, and The heating device 46 is attached to the inlet side to preheat.

In addition, the plasma reforming reactor (4) is divided into two types, the wire type (wire type) and the fan type (gliding type) according to the shape of the discharge electrode, the wire-type reforming reactor (4) is shown in Figure 2, Hollow rod-shaped body 43, wire discharge electrode 45 in the body 43, the heating device 46 attached to the gas inlet side of the body 43 and the end of the body 43 outlet 42 side It consists of an observation window 47 provided in. Here, the rod-shaped body 43 is preferably made of a stainless circular tube, and gas outlets 41 and 42 are formed at both ends. The wire discharge electrode 45 is made of, for example, nickel-chromium material, and is arranged long along the axis in the body 43. In addition, the inlet 41 side end of the wire discharge electrode 45 is provided with a heating device 46 for preheating the gas before entering the body 43 through the inlet, the outlet side of the body 43 Observation window 47 is installed to look inside the reactor (4). Accordingly, the biogas supplied from the gas storage tank 3 is introduced into the heating device, that is, the gas inlet 48 of the heater 46, is preheated, and then supplied into the reactor body 43 to generate a reforming reaction, thereby producing syngas. do. Such a wire reforming reactor is useful when used for pulsed plasma reforming in which periodic pulses are generated at nanosecond intervals to which high voltage low current of direct current is applied.

As another embodiment of the reforming reactor (4), the fan-shaped reforming reactor (104) shown in FIG. 3 also has a large outer tube (142), inner cylinder (143), discharge electrode (146), and spray nozzle (149) so as to take the form of a double tube as a whole. ), An annular diaphragm 151, a gas heater 154, and an observation window 155. Here, the outer cylinder 142 is a cylindrical body installed between the gas introduction unit 14 and the syngas storage unit 16 is to surround the inner cylinder 143, the inlet connected to the gas introduction unit 14 on the lower side ( 141, the connector 144 is connected to the injection nozzle 149 on one side of the upper end, respectively, the gas heater 154 is provided on the inner peripheral surface of the outer cylinder 142.

The cylindrical inner cylinder 143 which is installed coaxially in the outer cylinder 142 so as to form a preheating passage 153 between the outer cylinder 142 and the inner circumferential surface thereof has a syngas storage unit 15 through the outlet 145. And a plurality of holes 157 for mounting a pressure gauge or thermocouple on the side wall surface or for collecting a sample, and extend outward through the outer cylinder 142. In addition, a plurality of fan-shaped discharge electrodes 146 are radially arranged inside the inner cylinder 143 to be fixed to the cover 147 to receive power from the power supply device 5. It consists of four plates and faces two axisymmetrically. Injection nozzle 149 is installed to penetrate the cover 147 at the center position of the discharge electrode 146 radially arranged, the injection nozzle 149 is connected to the preheating passage 153 through the connector 144, the inlet The biogas flowing into 141 and preheated by the heater 154 is sprayed from above the inner cylinder 143. In addition, an annular diaphragm 151 is attached to an inner wall surface middle portion of the inner cylinder 143 to divide the inner cylinder 143 into an upper plasma generating unit 148 and a lower reaction terminating unit 150. 150 is connected to the discharge electrode 146 portion of the inner cylinder 143 through the central through hole 158 of the annular diaphragm 151. In addition, an observation window 155 is formed at a lower surface of the inner cylinder 143 so that plasma generation can be observed inside the inner cylinder 143. Therefore, since the biogas is injected into the reactor 104 by the nozzle 149 having an inner diameter of 1.8 mm, the fluid flow in the plasma generator 9 is continuously circulated, and the plasma is generated at the reaction terminator 14. The radicals generated in section 148 are extinguished by the reaction.

The steam generator 8 shown in FIG. 4 is a device for supplying steam to the plasma reforming reactor 4, and constitutes a part of the steam supply system 18 for supplying steam to the reactor 4 while finely controlling the supply amount. Here, the steam supply system 18, as shown in Figure 4, the steam generator 8, the water tank (8) and the water tank (8) connected to the steam generator 8 is a cheap inert gas It consists of the nitrogen cylinder 6 which supplies nitrogen of high pressure. Accordingly, the water tank 7 is compressed by high pressure nitrogen and finely regulates the water stored therein by the pressure by the metering valve 19 to uniformly supply the steam generator 8 via the flow meter 20.

In addition, as shown in FIG. 5, the steam generator 8 includes a gas pipe 80, a water supply pipe 83, an atomizing nozzle 85, and a heating rod 90. Here, the gas pipe 80 has an inlet port 81 connected to the gas inlet 14 and an exhaust port 82 connected to the syngas storage unit 15 at both ends thereof, and the water tank 7 to the middle part of the inner space. ) Connected to the water supply pipe 83 is extended, the heating rod 90 is extended to the opposite side, between the water supply pipe 83 and the heating rod 90 atomization nozzle 85 coupled to the tip of the water supply pipe 83 It is attached to this inner peripheral surface. In addition, the atomization nozzle 85 is connected to the gas injection path 89 through the shaft diameter portion 87 of the nozzle hole 86, the spray is sprayed from the atomization nozzle 85 is heated to the heating rod 90 Is heated and evaporated to water vapor.

The syngas storage unit 15 connected to the output side of the plasma reforming reactor 4 is a portion for separating and storing water from the syngas generated in the plasma reforming reactor 4 and storing the water as shown in FIG. In the case of the first embodiment of the invention, it is composed of a gas-liquid separator 9 for separating moisture from the syngas generated in the plasma reforming reactor 4 and a storage unit 15 for storing the gas-separated syngas.

In addition, as a second embodiment of the syngas storage unit 15, the plasma reforming apparatus as shown in FIG. 6 is largely composed of a CO converter 11, a gas-liquid separator 12, and a fuel cell 13 as shown. Here, the CO converter 11 converts CO in the syngas generated in the plasma reforming reactor 4 into CO ₂ , and the gas-liquid separator 12 separates water from the syngas delivered from the CO converter 11. Do it. In addition, the fuel cell 13 connected to the output side of the gas-liquid separator 12 is configured to store the high concentration H ₂ discharged from the gas-liquid separator 12.

Now, the plasma reforming method by the plasma reforming apparatus of the biogas configured as described above will be described.

First, according to the first embodiment of the present invention shown in Figure 1, to produce a synthesis gas by reforming the biogas, the process is largely biogas introduction step (S10), steam supply step (S20), plasma reforming It consists of a step (S30), the synthesis gas storage step (S40). Among these, in the first step, the biogas introduction step S10, various biogases are supplied to the plasma reforming reactor 4 through the gas introduction unit 14 in the anaerobic reactor 1. Subsequently, in the steam supply step (S20), the biogas supplied from the biogas introduction unit 14 is mixed with the water vapor supplied from the steam generator 8 to supply steam into the reforming reactor 4. Next, in the plasma reforming step (S30), the biogas supplied from the gas introduction unit 14 is reformed through the wire reforming reactor 4 or the fan reforming reactor 104 shown in FIGS. 2 and 3. First, the biogas introduced by the heating devices 46 and 154 installed at the bio gas inlets 48 and 141 is preheated, and the biogas is reformed by low temperature or high temperature plasma generated from the wire or fan discharge electrodes 45 and 146. do. Finally, in the syngas storage step S40, the syngas generated by the plasma reforming reactor 4 or 104 is stored in the syngas storage unit 15 or 16, in the case of the first embodiment illustrated in FIG. 1. First, water is separated from the synthesis gas through the gas-liquid separator 9 of the synthesis gas storage unit 15, and then stored in the storage tank 10.

Meanwhile, in the case of the second embodiment of the present invention shown in FIG. 6, the synthesis gas is stored in the synthesis gas storage unit 16 through another synthesis gas storage step (S140). It is composed of CO conversion process (S141), water separation process (S142) and fuel cell supply process (S143). This of CO conversion process (S141) in is converted to CO in the synthesis gas produced in the plasma reforming reactor 4 by the CO converter (11) to CO _2. (S141) Subsequently, similarly to the gas-liquid separator (12) The water is separated from the synthesis gas supplied from the CO converter 11 (S142). Finally, H ₂ generated in the CO conversion process (S141) is supplied to the fuel cell 13 to manufacture a battery. (S143)

As described above, according to the plasma reforming method of the biogas according to the present invention, in the case of food waste treatment and wastewater treatment, biogas containing methane, carbon dioxide, and ammonia is generated in the anaerobic reactor 1 through the compressor 2. It is stored in the gas reservoir 3 and then supplied to the plasma reforming reactor 4. Natural gas, LPG, coal gasification fuel, liquid fuel, and by-product gas of about 9 to 18 carbons produced during the production of products from naphtha in petrochemical plants are stored directly in the gas storage tank (3) and reformed. It may be fed to the reactor 4.

The reforming reactor (4) is supplied with electricity from the power supply device (5), the low-temperature plasma (Non-Thermal Plasma (hereinafter referred to as NTP)) and high temperature plasma (High Temperature Plasma) reforming can be made. In particular, pulsed plasma reforming may be performed to increase the conversion rate. In this case, the pulse power supply is composed of a power regulator, a DC high voltage generator, a pulse generator, and a pulse transformer. For example, the maximum voltage is 50 kV and the minimum pulse length is 600 ns. A pulse with a maximum frequency of 900 Hz can be used.

In addition, a heating device 46 is used to maintain a high temperature of the plasma reforming reactor, and heat such as electric heater heating, heat storage biogas burner, and solar energy may be used.

Steam is supplied to the reforming reactor (4) from a steam feeder consisting of a water tank (7) and a steam generator (8) for steam reforming. When steam is added, there is an effect of suppressing the formation of carbon black along with the reforming reaction.

The gas generated from the reforming reactor 4 is a synthesis gas composed of intermediate products such as hydrocarbons and water in addition to hydrogen and carbon monoxide and stored in the storage tank 10 after the water is separated from the gas-liquid separator 9.

As a second embodiment of the present invention, in the case of the plasma reforming apparatus for producing hydrogen for fuel cells shown in FIG. 6, the gas-liquid separator 12 after converting carbon monoxide from the CO converter 11 to produce high concentration of hydrogen for fuel cells. The fuel cell 12 is supplied to the fuel cell 12 to be used for power generation.

The main reactions in the plasma reforming reactor are as follows.

Plasma Reforming (Cracking) Reaction

2CH ₄  → C ₂ H ₄  + 2H ₂

2CH ₄ → C ₂ H ₂  + 3H ₂

C ₂ H ₆ → C ₂ H ₄  + H ₂

C ₂ H ₆ → C ₂ H ₂  + 2H ₂

C ₃ H ₈ → C ₃ H ₆  + H ₂

C ₄ H ₁₀ → 2C ₂ H ₄  + H ₂

C ₄ H ₁₀ → 2C ₂ H ₂  + 3H ₂

2NH ₃  → 2NH ₂ + H ₂

2NH ₃  → N ₂ H ₄ + 2H ₂

Steam reforming reaction

CH ₄ + H ₂ O → CO + 3H ₂

C _n H _{2n + 2} + nH ₂ O → nCO + (2n + 1) H ₂

CO ₂ reforming

CH ₄ + CO ₂  → 2CO + 2H ₂

C _n H _{2n + 2} + nCO ₂  ¡Æ 2nCO + (n + 1) H ₂

-Forward and reverse reactions by water shifting

CO + H ₂ O → CO ₂ + H ₂

In addition, the conversion rate of biogas is biogas conversion rate where the propane and carbon dioxide in the simulated gas is converted to SynGas is expressed by Equation 1 below.

here, Is the biogas conversion rate (%), Is the inflow volume of C ₃ H ₈ (Nm ³ ), Is the outflow volume of C ₃ H ₈ (Nm ³ ).

In the case of pulse power, the power calculation is calculated by the following equation.

Where P is power (W), C is capacitor capacity (1 EA = 3600 x 10 ^-12 F ), v is pulse voltage (V), and f is frequency (Hz).

Experimental examples of the reformer according to the present invention are as follows. Simulated biogas is composed of C ₃ H ₈ (propane), C ₃ H ₆ (propylene) and CO ₂ (carbon dioxide), and these reforming reactions result in H ₂ (hydrogen), CH ₄ (methane) and C ₂ H ₂ (acetylene), carbon monoxide (CO) and C ₂ H ₄ (ethylene) are produced.

In the simulated gas / steam supply line, propane and carbon dioxide are mixed in a mixing tank, mixed with fully vaporized steam in a steam generator and fed to the reforming reactor.

The measurement / analysis line is divided into electrical characteristic measurement, temperature measurement and gas analysis. Electrical measurements are made by high voltage probes (Tektronixa P6015A), current probes (Tektronix A6303) and digital oscilloscopes (Tektronix TDS 3052). The temperature measurement consists of a K-type thermocouple with a diameter of 0.3 mm and a Fluke Hydra Data Logger. Gas analysis consists of sampling lines and gas chromatographs (SHIMADZU-14B).

As an experimental example of the reforming method according to the present invention, first, by sending air into the reactor to heat the temperature of the reforming reactor to 800 ℃ and stabilized by heating for 120 minutes by an electric heating device, the air supply is stopped and contains steam This experiment is carried out by feeding simulated biogas into the reactor. An example of starting characteristics of the reforming reactor is shown in FIG. 7.

The electrical characteristics of the pulse voltage and frequency control are controlled using the knob of the pulsed power supply, and the voltage, current and frequency are measured by a high voltage probe, a current probe and a digital oscilloscope, respectively. Propane and carbon dioxide, the components of the simulated biogas, are supplied from each bomber and mixed in a mixer after the flow rate is adjusted in the flow meter. In addition, the water vapor is controlled by a metering valve capable of fine control of the amount of water converted into the steam supply amount, and then flows together with the simulated biogas in the steam generator, and is converted into steam and sent into the reactor in a mixed gas state. Collection of SynGas takes place at sampling ports installed at the reactor outlet. The collected sample is passed through the cooling system and continuously flowed into the sampling loop of the gas chromatograph with water removed. For analysis, TCD detector was used. For the column, H ₂ and CO were Molecular Sieve (5A 80/100 mesh), C ₃ H ₈ , CO ₂ , CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₃ H ₆ used HayeSep R (100/120 mesh). The temperature was monitored in real time by a data analysis device by inserting a thermocouple in the reactor, the reactor inlet and the steam generator.

The experimental method was conducted by deciding the optimal condition through many repeated preliminary experiments and setting it as the reference condition (see Table 1). In this case, the reactor temperature was maintained at 800 ° C., and propane, carbon dioxide, and water vapor were supplied at 9 l / min, 6 l / min, and 13.7 l / min, respectively. In addition, the frequency is 500Hz, the voltage is supplied at 15.6 kV, the pulse power is obtained by the calculation of the equation (16) is 657 W. In addition, the pulse frequency, the biogas component ratio (C ₃ H ₈ / CO ₂ flow rate ratio), and the water vapor flow rate ratio (H ₂ O / TFR) which are considered to influence the reformation of the biogas. Flow rate ratio), gas flow rate, and pulse power change were carried out. The changes for each variable were 300 Hz to 600 Hz, 0.67 to 2.3, 0.42 to 0.52, 0.28 to 0.35 m / sec, and 270 W to 657 W.

Of the biogas components, C ₃ H ₈ represents the gas supplied from propane bomb (see Fig. 1). Actual components of propane bomb are C ₃ H ₈ 95%, C ₃ H ₆ 4.5% and other impurities. Consists of.

As a result, as a result of repeated experiments on the reforming characteristics of biogas using low-temperature pulsed plasma, the highest biogas conversion rate was selected as the reference condition in this experiment. Experimental conditions and data are shown.

Description: ¹⁾ TFR: total flow rate ( l / min), that is, biogas + H ₂ O, ²⁾ calculated by Equation 15

³⁾ ITMs: Intermediates, ie CH ₄ + C ₂ H ₂ + C ₃ H ₆ + CO + C ₂ H ₄

As a result of the reforming reaction under the standard conditions, the concentrations of the main syngases except the moisture generated from the biogas were H ₂ 64.5%, CH ₄ 8.1%, C ₂ H ₂ 6.7%, C ₃ H ₆ 4.9%, CO 0.8%, C ₂ H _{4 is} 0.4%. As can be seen from the concentration results, most of SynGas is hydrogen, and the ratio of hydrogen to intermediate is 3.1. In addition, biogas conversion rates of biogas components propane and carbon dioxide are 49.1% and 42.3%, respectively. Biogas conversion rate is the value calculated | required by Formula (15), respectively.

The study was performed for each variable according to the pulse frequency, biogas component ratio, water vapor flow rate, gas flow rate, and pulse power variation that are expected to affect the reforming reaction characteristics of biogas.

First, in the pulse frequency, FIG. 8A is an experimental result when only the frequency is changed from 300 Hz to 600 Hz under reference conditions in order to grasp the reforming characteristics of the biogas according to the change in the pulse frequency.

Figure 8a shows the concentration of the selected representative gas in the synthesis gas. As already mentioned, the simulated biogas is composed of C ₃ H ₈ , C ₃ H ₆ and CO ₂ , and its component ratio is 57% 2.7% 40%, respectively. However, due to the reforming reaction, the concentrations of C ₃ H ₈ and CO ₂ are reduced and converted to H ₂ . However, C ₃ H ₆ is slightly increased in preference to the cracking reaction, which is a plasma reforming reaction of Equation 5, rather than a decrease caused by steam and carbon dioxide reforming reactions (see Equations 2 and 4). While the pulse frequency is the average concentration of H ₂ at 500Hz is shown the maximum value to 64.5%, the average concentration of the components of the bio-gas, C ₃ H ₈ and C ₃ H ₆ are shown the minimum value of 30.6% and 4.9% each of CO ₂ The average concentration of is almost constant at 23.1% without significant change. This is because most of C ₃ H ₈ and C ₃ H ₆ are converted to H ₂ by steam and cracking reforming rather than carbon dioxide reforming.

Figure 8b shows the biogas conversion and the ratio of hydrogen and intermediates in the syngas produced. Propane has a maximum conversion rate of 49.1% at a frequency of 500Hz, while carbon dioxide has a maximum conversion rate of 43.3% at 450Hz. Therefore, as already mentioned in FIG. 8a, it can be seen that most of the conversion to H ₂ is due to steam and cracking reforming rather than carbon dioxide reforming at a frequency of 500 Hz. In addition, at 500 Hz, the ratio of hydrogen to intermediate product has a maximum value of 3.1, which means that the conversion of hydrogen to clean fuel at this frequency is higher than that of other intermediate products.

In addition, in the biogas component ratio, FIG. 9 changes only the component ratio (C ₃ H ₈ / CO ₂ ) of propane and carbon dioxide from 0.67 to 2.3 in order to simulate various biogases while maintaining other variables the same as the reference conditions. Experimental results when

Figure 9a shows the biogas conversion and the ratio of hydrogen and intermediates. In both propane and carbon dioxide, the biogas conversion rate increases as the component ratio increases, and then decreases again after the conversion ratio reaches a maximum when the component ratio is 1.5 and 1, respectively. In addition, the conversion rate of propane shows a great change in the composition ratio change compared to the carbon dioxide conversion rate. The ratio of hydrogen and intermediates also shows similar trends, such as propane conversion, maximum when the component ratio is 1.5, and can also be seen in the H ₂ concentration of FIG. In addition, in the case of C ₃ H ₈ and CO ₂ , as the component ratio increases, the concentration of C ₃ H ₈ increases with increasing propane supply amount, and the concentration of CO ₂ decreases relatively. Therefore, it can be seen that in order to reform the biogas, which is composed of various component ratios, it is necessary to change an appropriate operating condition for each component ratio of the biogas.

In addition, in the steam flow rate ratio, FIG. 10 is a result of changing the steam flow rate ratio (H ₂ O / TFR) to 0.42 to 0.52 in order to grasp the reforming characteristics according to the change in the amount of steam during steam reforming of the biogas.

As can be seen in FIG. 10A, the concentration of H ₂ increases rapidly as the steam flow rate ratio increases, because the steam reactor reforming and steam conversion reactions have the forward priority. However, the steam flow rate ratio reached a maximum value of 0.48 and then started to decrease again because of the low density density of C ₃ H ₈ and C ₃ H ₆ , which are the main components of H ₂ production in biogas due to the increase in water vapor volume. This is because the reaction is not effective. C ₃ H ₈ at the steam flow rate ratio where the concentration of H ₂ has a maximum value. The concentration shows the minimum value, which means that C ₃ H ₈ This is because the conversion to H ₂ is the largest, which can also be confirmed in the propane conversion of FIG. 10B. However, the CO ₂ concentration and the carbon dioxide conversion rate do not change significantly with the change of the steam flow rate ratio.

In the gas flow rate change, FIG. 11 is an experimental result when the flow rate of the biogas flowing into the reactor was changed to 0.28 to 0.35 m / sec. As the diameter of the reactor is the same, an increase in flow rate of gas means a decrease in residence time.

As can be seen in Figure 11a as the flow rate of the gas increases the concentration of H ₂ increases to have a maximum value, because the amount of conversion to hydrogen is increased due to the increase in the amount of biogas and the concentration of H ₂ is increased and Figure 11b It can also be seen in the ratio of hydrogen to intermediate products. However, the concentration of H ₂ decreases after showing a maximum value because the sufficient reforming reaction is difficult because the residence time in the reactor is reduced due to the limitation of the present pulse plasma reactor capacity.

In addition, as can be seen in FIG. 11B, the concentration of H ₂ has a high value at the gas velocity of 0.32 m / s, which shows the maximum value, but reaches a maximum at the gas velocity of 0.28 m / s, which is CH ₄ of FIG. 11A. This is because the residence time is long enough to generate intermediate products, as can be seen from the concentrations of C ₂ H ₂ and C ₂ H ₄ . However, the carbon dioxide conversion rate decreased continuously with increasing gas velocity.

Finally, in the pulse power change,

12 shows experimental results when the pulse power is changed from 270 W to 657 W. FIG. The pulse power is obtained by Equation 11 as already mentioned.

As can be seen from the result of FIG. 12A, while C ₃ H ₈ gradually decreases as power increases, The production of H ₂ is increased. This is because, as the electric energy increases in the reactor, radicals with high reactivity increase, and the reforming reaction proceeds actively.

In addition, as the power increases, the ratio between the hydrogen and the intermediate product increases as shown in FIG. 12B, which means that the intermediate product decreases relatively and the hydrogen, which is a clean fuel, increases. It is difficult to accurately determine the biogas conversion rate as a result of FIG. 12B, but it can be seen that the conversion rate has a maximum value at a specific voltage when considering the concentrations of intermediate products CH ₄ and C ₂ H ₂ . But more research is needed.

As a result, the results of the study on the reformation of biogas using low-temperature pulsed plasma are as follows.

SynGas produced based on the optimum biogas conversion rate in this wire type reformer was H ₂ 64.5%, CH ₄ 8.1%, C ₂ H ₂ 6.7%, C ₃ H ₆ 4.9%, CO 0.8%, C ₂ H _{4 is} 0.4%, the conversion of propane and carbon dioxide is 49.1% and 42.3%, respectively, and the ratio (H ₂ / ITMs) of hydrogen and intermediates (see description in Table 1) is 3.1. The reforming characteristics were identified according to the pulse frequency, biogas component ratio, water vapor flow ratio, gas flow rate, and pulse power change. As a result, the propane conversion rate increased as the value of the variable increased except the pulse power change. Hz, 1.5, 0.52, 0.32 m / s was shown and then decreased again. However, in the case of pulse power change, the biogas conversion rate gradually increased as the power increased. In addition, for all variables, the ratio of hydrogen and intermediate products was large when the conversion of propane gas was maximum.

As described above, according to the plasma reforming method and apparatus for biogas for syngas / hydrogen production according to the present invention, the volatile organic compounds of the biogas are safely recycled by recycling the biogas into high quality synthetic gas rather than directly burning it. The treatment will significantly reduce odor and greenhouse gas emissions.

While the invention has been shown and described with respect to particular embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention as indicated by the appended claims. Anyone can easily know.

1 is a schematic view showing the overall configuration of a plasma reforming method and apparatus for syngas production according to a first embodiment of the present invention.

Figure 2 is a schematic diagram showing the configuration of a wire-type reforming reactor of the reforming reactor shown in FIG.

Figure 3 is a schematic diagram showing the configuration of a fan-type reforming reactor of the reforming reactor shown in FIG.

Figure 4 is a schematic diagram showing the configuration of the steam supply equipment applied to the configuration shown in FIG.

5 is a schematic view showing the configuration of the steam generator shown in FIG.

Figure 6 is a schematic diagram showing the overall configuration of a plasma reforming method and apparatus for producing hydrogen for fuel cells according to a second embodiment of the present invention.

7 is a graph showing the starting characteristics of the reforming reactor.

8 is a graph showing the reforming characteristics according to the change in the pulse frequency, Figure 8a shows the concentration of the selected synthesis gas, Figure 8b shows the conversion rate and H ₂ / intermediate ratio of the biogas, respectively.

9 is a graph showing the reforming characteristics according to the change of the biogas component ratio, FIG. 9A shows the biogas conversion rate and the H ₂ / intermediate ratio, and FIG. 9B shows the concentration of the selected syngas.

10 is a graph showing the reforming characteristics according to the water vapor flow rate change, FIG. 10A shows the concentration of the selected syngas, and FIG. 10B shows the biogas conversion rate and the H ₂ / intermediate ratio, respectively.

11 is a graph showing the reforming characteristics according to the gas flow rate change, FIG. 11A shows the concentration of the selected syngas, and FIG. 11B shows the biogas conversion rate and the H ₂ / intermediate ratio, respectively.

12 is a graph showing the reforming characteristics according to the pulse power change, FIG. 12A shows the concentration of the selected syngas, and FIG. 12B shows the biogas conversion rate and the H ₂ / intermediate ratio, respectively.

Explanation of symbols on main parts of drawing

2: compressor 3: gas reservoir

4,104: plasma reforming reactor 5: power supply device

7: water tank 8: steam generator

9,12: gas-liquid separator 10: reservoir

11: CO converter 13: fuel cell

14 gas introduction unit 15,16 synthesis gas storage unit

Claims (13)

A biogas introduction step (S10) of supplying various biogases to the plasma reforming reactor (4) via the gas introduction unit (14); Steam supply step (S20) for supplying steam to the plasma reforming reactor (4) from the steam generator (8); A plasma reforming step (S30) of heating the biogas supplied from the gas introducing unit 14 by a heating device 46 and then reforming the biogas supplied by the low temperature plasma or the high temperature plasma generated in the plasma reforming reactor (4); And Biogas, characterized in that consisting of; gas separation step (S40) for separating the moisture from the synthesis gas produced in the plasma reforming reactor (4) by the gas-liquid separator (9) and storing in the storage tank (10); Plasma reforming method. According to claim 1, The syngas storage step (S140) is a process of converting CO in the syngas generated in the plasma reforming reactor (4) to CO ₂ by the CO converter 11 (S141), the CO by the gas-liquid separator 12 Separating water from the synthesis gas having undergone the conversion process (S141) (S142); And supplying H ₂ generated in the CO conversion process (S141) to a fuel cell (S143). According to claim 1, The biogas stored and reformed in the gas introduction unit 14 may be replaced with any one of natural gas, LPG, liquid fuel, coal gasification fuel, and by-product gas. A gas introduction unit 14 for compressing and storing various biogases, A plasma reforming reactor (4) for preheating the biogas supplied from the gas introduction unit (14) with a heating device (46) to be reformed by the plasma generated therein; A steam generator (8) for supplying steam to the plasma reforming reactor (4), and Biogas plasma reformer comprising a syngas storage unit (15) for separating and storing water from the syngas generated in the plasma reforming reactor (4). The method of claim 4, wherein The syngas storage unit 16 separates moisture from the syngas from the CO converter 11 and the CO converter 11 for converting CO in the syngas generated in the plasma reforming reactor 4 into CO ₂ . A gas reforming device comprising: a gas-liquid separator (12) and a fuel cell (13) for storing the high concentration H ₂ discharged from the gas-liquid separator (12). The method according to claim 4 or 5, The heating device 46 is a plasma reforming apparatus of a biogas, characterized in that any one of an electric heater, a heat storage biogas burner, a solar cell. The method according to claim 4 or 5, The plasma reforming reactor (4) has a rod-shaped body (43) having gas outlets (41, 42) formed at both ends, a wire discharge electrode (45) arranged along an axis in the body (43), and the wire discharge electrode. 45 is a wire-type reactor consisting of a heating device 46 integrally attached to the side of the body 43 adjacent to one side end, and an observation window 47 mounted on one end surface of the body 43. Plasma reformer for biogas, characterized in that. The method according to claim 4 or 5, The plasma reforming reactor 104 forms a preheating passage 153 between the outer cylinder 142 through which the biogas is introduced through the inlet 141 connected to the gas introduction unit 14, and the inner circumferential surface of the outer cylinder 142. An inner cylinder 143 installed inside the outer cylinder 142 and connected to the syngas storage units 15 and 16 through an outlet 145, and the inner cylinder 143 connected to the power supply device 5. Of the plurality of fan-shaped discharge electrode 146 radially installed therein, the injection nozzle 149 is mounted through the cover 147 of the inner cylinder 143 at the center position of the discharge electrode 146, the inner cylinder 143 An annular diaphragm 151 mounted on the inner circumferential surface of the inner cylinder 143 and a gas installed on the inner circumferential surface of the outer cylinder 142 along the preheating passage 153 to form a reaction terminating portion 150 on the opposite side of the discharge electrode 146. Observation window (1) provided on the heater 154, and the reaction end portion 150 side wall of the inner cylinder (143) A plasma reforming apparatus for biogas, characterized in that the fan-type reactor consisting of 55). The method according to claim 4 or 5, The plasma reforming device of the biogas, characterized in that the power supply (5) connected to the plasma reforming reactor (4) is a pulsed power supply. The method of claim 7, wherein The plasma reforming device of the biogas, characterized in that the power supply (5) connected to the plasma reforming reactor (4) is a pulsed power supply. The method of claim 8, The plasma reforming device of the biogas plasma, characterized in that the power supply (5) connected to the plasma reforming reactor (104) is a pulsed power supply. The method of claim 4, wherein The steam generator 8 includes a cylindrical gas pipe 80 and a water tank 7 formed at both ends thereof with an inlet 81 connected to the gas inlet 14 and an exhaust port 82 connected to the syngas storage 15. Is connected to the front end of the water supply pipe 83, the water supply pipe 83 is extended to the middle portion of the gas pipe 80, is mounted on the inner peripheral surface of the gas pipe 80, the shaft diameter portion of the nozzle hole (86) The atomization nozzle 85 through which the gas injection path 89 connected to the through hole 87 and the atomization nozzle sprayed from the atomization nozzle 85 are heated to evaporate to face the atomization nozzle 85. Biogas plasma reforming device comprising a heating rod (90) extending inside the gas pipe (80). A biogas introduction step (S10) of storing the biogas generated in the anaerobic reaction tank 1 through the compressor 2 in the gas storage tank 3 and then supplying the biogas to the plasma reforming reactor 4; Steam supply step (S20) for generating steam to the water supplied to the steam generator (8) from the water tank (7) to supply to the plasma reforming reactor (4); A preheating step (S30) of heating the biogas introduced into the plasma reforming reactor (4) by a heating device (46); A plasma reforming step (S40) of reforming the biogas supplied from the gas storage tank (3) by low temperature plasma or high temperature plasma generated in the plasma reforming reactor (4) with electricity supplied from a power supply device (5); And Biogas, characterized in that consisting of; gas separation step (S50) for separating the moisture from the synthesis gas generated in the plasma reforming reactor (4) by the gas-liquid separator (9) and storing in the storage tank (10); Plasma reforming method.