Storage device and method for leading out

Abstract

This storage device is for storing biogas containing methane gas and carbon dioxide, or concentrated gas obtained by concentrating the methane gas contained in the biogas. The storage device comprises: a tank that stores the biogas or the concentrated gas, and that includes an adsorbing material that adsorbs the biogas and the concentrated gas; and introduction / lead-out tubing that is connected to the tank and that is for introducing the biogas or the concentrated gas to the tank, or for leading out the biogas or the concentrated gas from the tank.

Description

Storage device and extraction method

[0001] The present disclosure relates to a storage device and a delivery method.

[0002] In recent years, biogas derived from livestock manure such as dairy and beef cattle has been attracting attention due to issues such as global warming and the depletion of fossil fuels. Biogas has been generated mainly at large ranches using generators and sold as electricity. However, small and medium-sized ranches that do not have generators have not been able to fully utilize biogas. In addition, due to a lack of power transmission networks, even if electricity generation is possible, it has been difficult to sell the electricity.

[0003] Therefore, a method is being considered in which the collected biogas is stored on each farm in a storage device filled with an adsorbent, and then transported to a collection site for separation and purification. This type of biogas handling is thought to have characteristics similar to the conventional separation and purification of natural gas.

[0004] Patent Document 1 (JP 2002-267097 A) discloses a storage device that adsorbs natural gas using an adsorbent filled in a pressure device, and also discloses that when desorbing natural gas from the adsorbent, desorption can be promoted by heating.

[0005] Patent Document 2 (JP 2008-240835 A) discloses a method for recovering and reusing gases such as natural gas by adsorbing them into a pressure-resistant container filled with an adsorbent, and also discloses that the pressure-resistant container is mounted on a vehicle and that the heat of adsorption and desorption is regulated by a temperature regulation unit.

[0006] JP 2002-267097 A JP 2008-240835 A

[0007] The device described in Patent Document 1 is designed for stationary use and long-term storage of natural gas. Therefore, it is not intended for portable use or for short-term adsorption / desorption of natural gas. In addition, a heater is provided on the side of the pressure device to promote desorption, but this configuration is also intended for stationary use where a heat source can be secured.

[0008] In Patent Document 2, a heat medium pipe and a temperature adjustment unit are provided in a pressure-resistant container, but the specific mechanism is not disclosed.

[0009] An object of the present disclosure is to provide a storage device that can efficiently discharge biogas or concentrated biogas gas, and a method for discharging biogas or concentrated biogas gas.

[0010] [1] A storage device for storing biogas containing methane gas and carbon dioxide gas, or concentrated gas obtained by concentrating the methane gas in the biogas, comprising: a tank for storing the biogas or the concentrated gas, the tank containing an adsorbent that adsorbs the biogas and the concentrated gas; and an inlet / outlet pipe connected to the tank, for introducing the biogas or the concentrated gas into the tank and for discharging the biogas or the concentrated gas from the tank.

[0011] [2] The storage device described in [1], wherein the inlet and outlet piping is connected to a first side of the tank.

[0012] [3] The storage device described in [2], wherein the tank has a longitudinal direction and a lateral direction, and the first side is one of the sides that intersects with the longitudinal direction.

[0013] [4] The storage device described in [3], which is installed and used so that the longitudinal direction is horizontal.

[0014] [5] The storage device described in [4], wherein the inlet / outlet piping includes a first inlet / outlet piping and a second inlet / outlet piping, the tip of the first inlet / outlet piping and the tip of the second inlet / outlet piping are installed within the tank, and the tip of the first inlet / outlet piping is located closer to the first side surface than the tip of the second inlet / outlet piping.

[0015] [6] The storage device described in [5] is provided with a return pipe for connecting the tank and the inlet / outlet pipe, the return pipe being for returning at least a portion of the biogas or concentrated gas discharged from the tank to the tank, wherein the return pipe is connected to the first side, the tip of the return pipe is installed within the tank, the tip of the first inlet / outlet pipe is located closer to the first side than the tip of the return pipe, the tip of the second inlet / outlet pipe is located closer to the second side than the tip of the return pipe, and the second side is the side opposite the first side.

[0016] [7] A storage device as described in [6], wherein the first inlet / outlet pipe, the second inlet / outlet pipe, and the return pipe are connected to the vertical lower part of the first side surface.

[0017] [8] The storage device according to any one of [3] to [7], further comprising an adsorbent filling section for filling the adsorbent, the adsorbent filling section being installed on the first side surface.

[0018] [9] A storage device described in any of [6] to [8], comprising a first valve for opening and closing the inlet and outlet pipes, and a second valve for opening and closing the return pipes, wherein the first valve and the second valve are provided on the first side surface side.

[0019]

[10] A storage device described in any one of [1] to [9] that is portable.

[0020]

[11] A storage device described in any one of [1] to

[10] , wherein the biogas is a gas derived from at least one selected from the group consisting of livestock manure and food waste.

[0021]

[12] A method for discharging the biogas or the concentrated gas from the storage device described in any one of [1] to

[11] , comprising a discharging step of discharging the biogas or the concentrated gas from the tank.

[0022]

[13] The discharge method according to

[12] , wherein the tank has a first side surface, and the biogas or the concentrated gas discharged in the discharge step is discharged from the first side surface.

[0023]

[14] The extraction method described in

[13] , further comprising a return process of returning at least a portion of the biogas or concentrated gas extracted in the extraction process to the tank, wherein at least a portion of the biogas or concentrated gas extracted in the extraction process is returned to the tank from the first side, and the return process is carried out while the extraction process is being carried out.

[0024]

[15] The method for extracting biogas according to

[14] , wherein in the return step, at least a portion of the biogas or concentrated gas extracted from the tank is compressed and returned to the tank.

[0025] According to the present disclosure, it is possible to provide a storage device that can efficiently discharge biogas or concentrated biogas gas, and a method for discharging biogas or concentrated biogas gas.

[0026] FIG. 1 is a schematic diagram showing an example of the configuration of a storage device in this embodiment. FIG. 2 is a schematic diagram showing another example of the configuration of a storage device in this embodiment. FIG. 3 is a schematic diagram showing another example of the configuration of a storage device in this embodiment. FIG. 4 is a schematic diagram showing another example of the configuration of a storage device in this embodiment. FIG. 5 is a schematic diagram showing another example of the configuration of a storage device in this embodiment. FIG. 6 is a schematic diagram showing another example of the configuration of a storage device in this embodiment. FIG. 7 is a schematic diagram showing an example of a tank provided in the storage device in this embodiment. FIG. 8 is a schematic diagram showing another example of a tank provided in the storage device in this embodiment. FIG. 9 is a schematic diagram showing another example of a tank provided in the storage device in this embodiment. FIG. 10 is a schematic diagram showing an example of a method of filling a tank provided in the storage device in this embodiment with an adsorbent. FIG. 11 is a schematic diagram showing another example of a tank provided in the storage device in this embodiment. FIG. 12 is a schematic diagram showing another example of a tank provided in the storage device in this embodiment. FIG. 13 is a schematic diagram showing a vehicle equipped with the storage device in this embodiment.

[0027] Hereinafter, embodiments of the present disclosure will be described, but the following description does not limit the scope of the claims.

[0028] 1 and 2 , a storage device 20 in this embodiment includes a tank 1 for storing biogas or concentrated gas obtained by concentrating methane gas in the biogas, and an inlet / outlet pipe 2 that is connected to the tank 1 and is used to introduce the biogas or concentrated gas into the tank 1 and to discharge the biogas or concentrated gas from the tank 1. The tank 1 is filled with an adsorbent that adsorbs the biogas and concentrated gas. The storage device 20 in this embodiment will be described below.

[0029] In the present embodiment, the term "biogas" refers to a gas derived from at least one selected from the group consisting of livestock manure and food waste, and contains at least methane and carbon dioxide (CO ２ The concentration of methane in the biogas is, for example, 50% by volume or more and 65% by volume or less, and the CO ２ The concentration of hydrogen sulfide in the biogas is, for example, 25% by volume or more and 40% by volume or less. The biogas may contain other gases such as nitrogen and oxygen. The concentration of nitrogen in the biogas may be, for example, 1% by volume or more and 15% by volume or less, and the concentration of oxygen in the biogas may be, for example, 0.1% by volume or more and 5% by volume or less. It is preferable that hydrogen sulfide and moisture have been removed from the biogas in advance.

[0030] <<Concentrated Gas>> In this embodiment, the term "concentrated gas" refers to a gas obtained by concentrating methane gas in biogas. The concentration of methane gas in the concentrated gas is, for example, 75% by volume or more and 97% by volume or less.

[0031] 7 is a schematic diagram showing an example of the tank 1 provided in the storage device 20 in this embodiment. The tank 1 stores biogas or concentrated gas. The tank 1 has a pressure-resistant structure.

[0032] The tank 1 preferably has a first side surface 3. In this case, the tank 1 preferably has a second side surface 7. The second side surface 7 is a side surface opposite to the first side surface 3.

[0033] The tank 1 preferably has a longitudinal direction and a lateral direction. When the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the first side surface 3 and the second side surface 7 are sides that intersect with the longitudinal direction. In other words, the first side surface 3 and the second side surface 7 are sides that are parallel to the lateral direction. Referring to FIG. 7 , the longitudinal direction is the left-right direction, and the lateral direction is the depth direction of the page. Furthermore, as shown in FIG. 7 , it is more preferable to install and use the tank 1 so that the longitudinal direction is horizontal.

[0034] The tank 1 is filled with an adsorbent. The adsorbent is methane and CO ２ An adsorbent capable of adsorbing the above is used. Examples of such adsorbents include activated carbon. Activated carbon is made from, for example, coconut shell, coal, charcoal, phenolic resin, etc. The activated carbon may be, for example, powdered activated carbon, crushed carbon, granulated carbon, etc. The particle size of the activated carbon may be, for example, 0.3 mm or more and 0.8 mm or less. In this embodiment, crushed carbon is preferably used.

[0035] The tank 1 may have an adsorbent filling section 4. There are no particular restrictions on where the adsorbent filling section 4 is installed, but when the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the adsorbent filling section 4 is preferably installed on the first side surface 3, as shown in FIG. 7 . By installing the adsorbent filling section 4 on the first side surface 3 and filling the adsorbent with the adsorbent filling section 4 at the top in the vertical direction, the adsorbent can be efficiently filled into the tank 1 (see FIG. 10 ). Furthermore, it is more preferable that the adsorbent filling section 4 be connected to the center of the first side surface 3.

[0036] Furthermore, the adsorbent can be filled more efficiently by providing a plurality of adsorbent filling sections 4. For example, as shown in Fig. 8, one adsorbent filling section 4 may be provided on the first side surface 3 and one on the top of the tank 1, or as shown in Fig. 9, one adsorbent filling section 4 may be provided on the first side surface 3 and three on the top of the tank 1. Note that the numbers of adsorbent filling sections 4 provided on the top of the tank 1 in Figs. 8 and 9 are merely examples and are not limited to these.

[0037] The tank 1 may have a frame 9. When the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the frame 9 may be provided on at least the first side surface 3, as shown in Fig. 11, or may be provided on both the first side surface 3 and the second side surface 7, as shown in Fig. 12.

[0038] <<Inlet / Outlet Piping>> The inlet / outlet pipe 2 is a pipe connected to the tank 1. The biogas or concentrated gas is introduced into or discharged from the tank 1 via the inlet / outlet pipe 2. That is, the inlet / outlet pipe 2 functions as an inlet pipe when the biogas or concentrated gas is introduced into the tank 1, and as an outlet pipe when the biogas or concentrated gas is discharged from the tank 1.

[0039] 3 and 4, the storage device 20 is required to have at least one inlet / outlet pipe 2, and preferably has two inlet / outlet pipes 2 (a first inlet / outlet pipe 2a and a second inlet / outlet pipe 2b). By providing the storage device 20 with the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b, the introduction rate and discharge rate of the biogas or concentrated gas can be increased. When the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b are preferably connected to the first side surface 3.

[0040] Furthermore, when biogas or concentrated gas is introduced into the tank 1, heat of adsorption is generated due to the adsorption of the biogas or concentrated gas, causing a rise in the temperature of the tank 1. Therefore, by introducing the biogas or concentrated gas through one of the inlet / outlet pipes 2 and releasing the heat of adsorption through the other inlet / outlet pipe 2, the rise in temperature of the tank 1 can be suppressed.

[0041] Furthermore, by providing the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b, biogas or concentrated gas can be introduced from one inlet / outlet pipe 2 and discharged from the other inlet / outlet pipe 2.

[0042] When biogas or concentrated gas is discharged from the tank 1 through one inlet / outlet pipe 2, the composition of the discharged biogas or concentrated gas may be biased. Therefore, by discharging the biogas or concentrated gas through two inlet / outlet pipes 2, the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b, the composition of the discharged biogas or concentrated gas can be made uniform.

[0043] The inlet / outlet pipe 2 is preferably connected to the first side surface 3 of the tank 1. When the inlet / outlet pipe 2 is connected to the first side surface 3 of the tank 1 and the adsorbent filling section 4 is provided on the first side surface 3 of the tank 1, the connection point of the inlet / outlet pipe 2 is preferably different from the installation point of the adsorbent filling section 4. In this case, the inlet / outlet pipe 2 is preferably connected to the lower part of the first side surface 3 in the vertical direction. Note that when the inlet / outlet pipe 2 consists of a first inlet / outlet pipe 2a and a second inlet / outlet pipe 2b, they are preferably connected in the same manner.

[0044] When the storage device 20 includes a single inlet / outlet pipe 2, the tip of the inlet / outlet pipe 2 may be installed inside the tank 1. When the storage device 20 includes a first inlet / outlet pipe 2a and a second inlet / outlet pipe 2b, and the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the tip of the first inlet / outlet pipe 2a and the tip of the second inlet / outlet pipe 2b are preferably installed inside the tank 1. In this case, the positions of the tips of the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b may be approximately the same position inside the tank 1, as shown in FIG. 4 . However, as shown in FIG. 3 , it is preferable that the tip of the first inlet / outlet pipe 2a be located closer to the first side surface 3 than the tip of the second inlet / outlet pipe 2b. In this way, the biogas or concentrated gas is discharged from different positions inside the tank 1, thereby making it possible to make the composition of the discharged biogas or concentrated gas uniform.

[0045] The tip of the inlet / outlet pipe 2 preferably has a backflow prevention structure such as a check valve from the viewpoint of preventing backflow of the adsorbent filled in the tank 1. There are no particular limitations on the backflow prevention structure, but examples thereof include a metal mesh, a cloth mesh, and a polymer membrane.

[0046] <<Return Pipe>> The return pipe 6 is a pipe that connects the tank 1 and the inlet / outlet pipe 2. At least a portion of the biogas or concentrated gas discharged from the tank 1 returns to the tank 1 via the return pipe 6. In this way, the composition of the discharged biogas or concentrated gas can be made uniform.

[0047] When the storage device 20 includes one inlet / outlet pipe 2 and one return pipe 6, and the tank 1 has a first side 3, a second side 7, a longitudinal direction, and a transverse direction, the ends of the inlet / outlet pipe 2 and the return pipe 6 are preferably installed within the tank 1. In this case, the positions of the ends of the inlet / outlet pipe 2 and the return pipe 6 may be approximately the same within the tank 1, but the end of the inlet / outlet pipe 2 is preferably located closer to the first side 3 or the second side 7 than the end of the return pipe 6. Positioning the ends of the inlet / outlet pipe 2 and the return pipe 6 at different locations prevents the biogas or concentrated gas returned via the return pipe 6 from being discharged from the inlet / outlet pipe 2 before being mixed within the tank 1. Furthermore, the end of the return pipe 6 is preferably located in the central portion of the tank 1 (away from the first side 3 and the second side 7). This allows the biogas or concentrated gas returned to the tank 1 to be uniformly mixed within the tank 1.

[0048] 5 and 6, when the storage device 20 includes a first inlet / outlet pipe 2a, a second inlet / outlet pipe 2b, and a return pipe 6, and the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, it is preferable that the ends of the first inlet / outlet pipe 2a, the second inlet / outlet pipe 2b, and the return pipe 6 are installed within the tank 1. In this case, the positions of the ends of the first inlet / outlet pipe 2a, the second inlet / outlet pipe 2b, and the return pipe 6 may be approximately the same within the tank 1 as shown in Fig. 6, but it is preferable that the end of the first inlet / outlet pipe 2a be located closer to the first side surface 3 than the end of the return pipe 6, and the end of the second inlet / outlet pipe 2b be located closer to the second side surface 7 than the end of the return pipe 6, as shown in Fig. 5. The end of the first inlet / outlet pipe 2a, the end of the second inlet / outlet pipe 2b, and the end of the return pipe 6 are located at different positions to prevent the biogas or concentrated gas returned via the return pipe 6 from being discharged from the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b before being mixed in the tank 1. In addition, it is preferable that the end of the return pipe 6 is located in the center of the tank 1. In this way, the biogas or concentrated gas returned to the tank 1 can be mixed uniformly in the tank 1.

[0049] The return pipe 6 is preferably connected to the first side surface 3 of the tank 1. When the return pipe 6 is connected to the first side surface 3 of the tank 1 and the adsorbent filling section 4 is provided on the first side surface 3 of the tank 1, the connection location of the return pipe 6 and the installation location of the adsorbent filling section 4 are preferably different. In this case, the return pipe 6 is preferably connected to a vertically lower portion of the first side surface 3. Also, when the inlet / outlet pipe 2 (including the case where the inlet / outlet pipe 2 consists of the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b) and the return pipe 6 are connected to the first side surface 3 of the tank 1 and the adsorbent filling section 4 is provided on the first side surface 3 of the tank 1, the same connection is preferably made.

[0050] The tip of the return pipe 6 preferably has a backflow prevention structure such as a check valve from the viewpoint of preventing backflow of the adsorbent filled in the tank 1. Examples of the backflow prevention structure include the same backflow prevention structures as those described above.

[0051] <<Valves>> The storage device 20 may include a first valve 5. The introduction of biogas or concentrated gas into the tank 1 and the discharge of biogas or concentrated gas from the tank 1 are regulated by the first valve 5. Furthermore, when the storage device 20 includes the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b and the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, the storage device 20 preferably includes the first valves 5a, 5b, and the first valves 5a, 5b are preferably provided on the first side surface 3 side. Providing the first valves 5a, 5b on the first side surface 3 side simplifies operation.

[0052] The storage device 20 may include a second valve 8. The return of the biogas or concentrated gas to the tank 1 via the return pipe 6 is regulated by the second valve 8. Furthermore, when the storage device 20 includes the first valve 5 (including the case where the first valve 5 is composed of the first valves 5a and 5b) and the second valve 8, and the tank 1 has a first side surface 3, a second side surface 7, a longitudinal direction, and a lateral direction, it is preferable that the first valve 5 and the second valve 8 are provided on the first side surface 3 side. Providing the first valve 5 and the second valve 8 on the first side surface 3 side makes operation easier.

[0053] <<Compression Means>> The storage device 20 in this embodiment may include a compressor 13. The compressor 13 compresses at least a portion of the biogas or concentrated gas discharged from the tank 1. The biogas or concentrated gas discharged from the tank 1 is at a low pressure. Furthermore, when the biogas or concentrated gas is discharged from the tank 1, the heat of desorption due to the desorption of the biogas or concentrated gas lowers the temperature of the tank 1. It is believed that the lowered temperature of the tank 1 inhibits the discharge of the biogas or concentrated gas. Therefore, by compressing at least a portion of the biogas or concentrated gas discharged from the tank 1 using the compressor 13 and returning it to the tank 1 via the return pipe 6, it is possible to inhibit the decrease in temperature of the tank 1 and promote the discharge of the biogas or concentrated gas. Furthermore, even when at least a portion of the biogas or concentrated gas discharged from the tank 1 is not returned to the tank 1 via the return pipe 6, the discharge of the biogas or concentrated gas can be promoted by increasing the pressure of the biogas or concentrated gas using the compressor 13.

[0054] Others The storage device 20 in this embodiment may include a heating means 11, a buffer tank 12, and a cooling means 14. These function when discharging biogas or concentrated gas.

[0055] The heating means 11 heats the discharged biogas or concentrated gas. The heating means 11 may be used when the temperature of the discharged biogas or concentrated gas is low. The buffer tank 12 temporarily stores the discharged biogas or concentrated gas. The cooling means 14 cools the compressed biogas or concentrated gas. The cooling means 14 may be used when the temperature of the compressed biogas or concentrated gas is high.

[0056] The storage device 20 in this embodiment is suitable for use in collecting biogas or concentrated gas derived from the excrement of livestock raised on a farm, for example. From this perspective, it is preferable to make the storage device 20 portable. An example of a portable device is a vehicle 15 (lorry) equipped with the storage device 20, as shown in FIG. 13 .

[0057] <Discharge Method> The discharge method in this embodiment includes a discharge step of discharging the biogas or the concentrated gas from the tank. Hereinafter, the discharge method in this embodiment will be described with reference to FIGS.

[0058] (Discharge Step) The discharge step is a step of discharging the biogas or the concentrated gas from the tank 1 .

[0059] In the storage device 20 of this embodiment, the biogas or concentrated gas is discharged from the tank 1 via the inlet / outlet pipe 2. Details of the tank 1 and the inlet / outlet pipe 2 are as described above.

[0060] The biogas or concentrated gas is preferably discharged from the tank 1 via the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b from the first side surface 3. This makes it possible to make the composition of the discharged biogas or concentrated gas uniform.

[0061] (Returning Step) The discharge method in this embodiment may include a returning step of returning at least a portion of the biogas or concentrated gas discharged in the discharging step to the tank 1. In this case, the returning step is performed while the discharging step is being performed.

[0062] In the storage device 20 of this embodiment, the biogas or concentrated gas is returned to the tank 1 via the return pipe 6. Details of the return pipe 6 are as described above.

[0063] It is preferable that at least a portion of the biogas or concentrated gas discharged in the discharge step is returned to the tank 1 from the first side surface 3. By carrying out the discharge step and the return step from the first side surface 3, the operation of each step can be easily performed.

[0064] The return process is carried out while the discharge process is being carried out. By carrying out the return process while the discharge process is being carried out, the composition of the discharged biogas or concentrated gas can be made uniform.

[0065] In the return process, it is preferable to compress at least a portion of the biogas or concentrated gas discharged from the tank 1 and return it to the tank 1. The biogas or concentrated gas discharged from the tank 1 is at a low pressure. Furthermore, when the biogas or concentrated gas is discharged from the tank 1, the heat of desorption caused by the desorption of the biogas or concentrated gas lowers the temperature of the tank 1. It is believed that the lowering of the temperature of the tank 1 inhibits the discharge of the biogas or concentrated gas. Therefore, by compressing at least a portion of the biogas or concentrated gas discharged from the tank 1 using the compressor 13 and returning it to the tank 1 via the return pipe 6, it is possible to inhibit the decrease in the temperature of the tank 1 and promote the discharge of the biogas or concentrated gas.

[0066] The following examples are provided to illustrate, but are not intended to limit the scope of the claims.

[0067] Example 1 An apparatus having the configuration shown in Figure 5 was prepared. Biogas derived from livestock manure was prepared. The biogas contained about 54% by volume of methane and about 10% by volume of CO ２ The biogas contained approximately 40% by volume of sodium, approximately 5% by volume of nitrogen, and approximately 1% by volume of oxygen. The components of the biogas were analyzed by gas chromatography. Activated carbon was filled into the tank 1 as an adsorbent. The biogas was then filled into the tank 1 via the first inlet / outlet pipe 2a. The temperature of the tank 1 after filling was 40°C.

[0068] Next, biogas was discharged from the tank 1 through the first inlet / outlet pipe 2a and the second inlet / outlet pipe 2b. The discharge amount of biogas was 100 Nm ３ / h. The discharged biogas was heated by the heating means 11 and stored in the buffer tank 12. The temperature of the discharged biogas was adjusted to 20°C by the heating means 11. The stored biogas was compressed to 0.85 MPaG by the compressor 13. The compressed biogas was cooled to 40°C by the cooling means 14. Thereafter, a portion of the biogas was returned to the tank 1 through the return pipe 6. The return amount of the biogas was 60 Nm ３ The biogas was extracted for 12 hours.

[0069] Comparative Example 1 Biogas was discharged in the same manner and under the same conditions as in Example 1, except that a portion of the discharged biogas was not returned to the tank 1 through the return pipe 6 .

[0070] <Evaluation> In Example 1 and Comparative Example 1, the composition of the biogas at point 1 in FIG. 5 immediately after the start of discharge and at the end of discharge, and the temperature of the tank 1 at the end of discharge were measured.

[0071] <Results> In Example 1, the biogas at point 1 in FIG. 5 immediately after the start of extraction was composed of about 51% by volume of methane and about 10% by volume of CO ２ The biogas at point 1 in Figure 6 at the end of extraction contained about 49 vol% methane and about 33 vol% CO ２ The gas contained about 40% by volume of sodium, about 10% by volume of nitrogen, and about 1% by volume of oxygen. The temperature of the tank 1 at the end of the extraction was 18°C.

[0072] On the other hand, in Comparative Example 1, the biogas at point 1 in FIG. 5 immediately after the start of extraction was composed of about 60% by volume of methane and about 10% by volume of CO ２ The biogas at point 1 in Figure 6 at the end of extraction contained about 55% by volume of methane and about 1% by volume of CO. ２ The gas contained about 39.5% by volume of sodium, about 5% by volume of nitrogen, and about 0.5% by volume of oxygen. The temperature of the tank 1 at the end of extraction was 5°C.

[0073] In Example 1, the composition of the biogas immediately after the start of discharge and at the end of discharge, and the temperature of the tank 1 before the start of discharge and at the end of discharge fluctuated little. On the other hand, in Comparative Example 1, the composition of the biogas immediately after the start of discharge and at the end of discharge, and the temperature of the tank 1 before the start of discharge and at the end of discharge fluctuated more than in Example 1. Therefore, it is considered that by compressing at least a portion of the biogas discharged from the tank 1 and returning it to the tank 1, the composition of the biogas discharged and the temperature of the tank 1 can be stabilized.

[0074] In this way, by using the storage device and extraction method described in the present disclosure, biogas can be efficiently extracted. Furthermore, since the present disclosure makes effective use of livestock manure that would otherwise be discarded, it can contribute to some of the activities of the Sustainable Development Goals (SDGs).

[0075] The embodiments and examples disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0076] DESCRIPTION OF SYMBOLS 1 Tank, 2 Inlet / Outlet Pipe, 2a First Inlet / Outlet Pipe, 2b Second Inlet / Outlet Pipe, 3 First Side, 4 Adsorbent Filling Section, 5, 5a, 5b First Valve, 6 Return Pipe, 7 Second Side, 8 Second Valve, 9 Frame, 11 Heating Means, 12 Buffer Tank, 13 Compressor, 14 Cooling Means, 15 Vehicle, 20 Storage Device.

Claims

1. A storage device for storing biogas containing methane gas and carbon dioxide gas, or concentrated gas obtained by concentrating the methane gas in the biogas, comprising: a tank for storing the biogas or the concentrated gas, containing an adsorbent for adsorbing the biogas and the concentrated gas; and piping connected to the tank, for introducing the biogas or the concentrated gas into the tank and for discharging the biogas or the concentrated gas from the tank.

2. The storage device of claim 1, wherein the inlet and outlet piping is connected to a first side of the tank.

3. The storage device of claim 2, wherein the tank has a longitudinal direction and a transverse direction, and the first side is one side that intersects with the longitudinal direction.

4. The storage device according to claim 3, which is installed and used such that the longitudinal direction is horizontal.

5. The storage device described in claim 4, wherein the inlet / outlet piping includes a first inlet / outlet piping and a second inlet / outlet piping, an end of the first inlet / outlet piping and an end of the second inlet / outlet piping are installed within the tank, and the end of the first inlet / outlet piping is located closer to the first side than the end of the second inlet / outlet piping.

6. A storage device as described in claim 5, further comprising a return pipe for connecting the tank and the inlet / outlet pipe, for returning at least a portion of the biogas or concentrated gas discharged from the tank to the tank, the return pipe being connected to the first side, an end of the return pipe being installed within the tank, an end of the first inlet / outlet pipe being positioned closer to the first side than the end of the return pipe, an end of the second inlet / outlet pipe being positioned closer to the second side than the end of the return pipe, and the second side being the side opposite the first side.

7. The storage device of claim 6, wherein the first inlet / outlet pipe, the second inlet / outlet pipe and the return pipe are connected to a vertically lower portion of the first side surface.

8. A storage device as claimed in any one of claims 3 to 7, comprising an adsorbent filling section for filling the adsorbent, the adsorbent filling section being provided on the first side surface.

9. A storage device as described in any one of claims 6 to 8, comprising a first valve for opening and closing the inlet and outlet pipes, and a second valve for opening and closing the return pipes, the first valve and the second valve being provided on the first side.

10. A storage device according to any one of claims 1 to 9, which is portable.

11. The storage device according to any one of claims 1 to 10, wherein the biogas is a gas derived from at least one selected from the group consisting of livestock manure and food waste.

12. A method for discharging the biogas or the concentrated gas from a storage device according to any one of claims 1 to 11, comprising a discharging step of discharging the biogas or the concentrated gas from the tank.

13. The extraction method according to claim 12, wherein the tank has a first side surface, and the biogas or the concentrated gas extracted in the extraction step is extracted from the first side surface.

14. The extraction method according to claim 13, further comprising a return process of returning to the tank at least a portion of the biogas or concentrated gas extracted in the extraction process, wherein at least a portion of the biogas or concentrated gas extracted in the extraction process is returned to the tank from the first side, and the return process is performed while the extraction process is being performed.

15. The method according to claim 14, wherein in the return step, at least a portion of the biogas or concentrated gas discharged from the tank is compressed and returned to the tank.

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