JP4885465B2 - Low boiling point liquefied gas transport equipment - Google Patents

Description

  The present invention relates to a boil-off gas processing method, a processing apparatus, and a low-boiling-point liquefied gas transport apparatus using gas adsorbing capacity change due to temperature change of an adsorbent, and more particularly methane, ethane, propane and other lower hydrocarbons, natural The present invention relates to a processing method, a processing apparatus, and a low-boiling-point liquefied gas transport apparatus for boil-off gas generated in a low-temperature liquid tank used for storage and transport of low-temperature liquefied gas such as gas, hydrogen, or carbon dioxide. In the present specification, these boil-off gases are also referred to as “BOG” as appropriate.

  A tank is usually used for storage and transportation of low-temperature liquefied gas such as liquefied natural gas (also referred to as “LNG” where appropriate). The tank is normally insulated with a heat insulating material or the like, but heat still enters the tank from the outside environment, and a part of the liquefied gas in the tank is vaporized and evaporated to increase the internal pressure of the tank. If this tank internal pressure rises and exceeds the design pressure resistance of the tank, the tank will be damaged, and there will be dangers such as gas leakage and explosion. As a method for avoiding this problem, it is conceivable to release BOG generated in the tank from the tank, but when BOG is a flammable gas or a toxic gas, it cannot be released to the atmosphere.

  Conventionally, for example, there are various techniques for treating LNG boil-off gas. As one of them, (a) LNG boil-off gas is boosted using an electric booster, and is sent and delivered. FIG. 9 is a diagram showing an example of this, and LNG carried by a lorry vehicle or the like is stored in the tank 11. The LNG in the LNG tank 11 is vaporized by the vaporizer 13 and then used as a fuel for a natural gas vehicle or supplied to a city gas main pipeline.

  On the other hand, the boil-off gas generated in the LNG tank 11 is always mixed with the natural gas vaporized by the vaporizer 13 after being boosted to the delivery pressure (medium pressure or high pressure: 1 to 7 MPa) by the electric booster (compressor) 12. They are processed by being delivered as fuel for natural gas vehicles or sent to city gas pipelines. However, since this technology uses an electric booster, its driving power is increased. The power unit required for boosting the LNG boil-off gas is 100 to 300 kWh / t, and the power cost required for this is estimated to be several billion yen nationwide, which is very expensive.

  Also, (b) Japanese Patent Application Laid-Open No. 2000-213697 discloses a technique of collecting LNG boil-off gas by adsorbing it on an adsorbent and delivering it by opening a container at another site. FIG. 10 is a diagram shown in the publication. An adsorption-type BOG holder 24 is arranged branched from the BOG line 22 from the LNG tank 21. 23 and 25 are BOG lines before and after the adsorption-type BOG holder 24. Excess BOG is adsorbed and filled from the LNG tank 21 via the line 22 into the adsorption-type BOG holder 24 under the vapor pressure of the LNG tank 21 (usually about 5 to 10 kPa). In FIG. 10, 27 is a pump arranged in the LNG outlet pipe 26 from the LNG tank 21, and 28 is an LNG vaporizer.

  However, the technique of the above publication is gas adsorption at room temperature on the adsorbent, and gas adsorption by physical adsorption on the surface of the porous material. Since physical adsorption uses an equilibrium phenomenon with pressure, the adsorption rate is slow, and the amount of gas adsorption to the porous material is small at room temperature. For this reason, in order to collect | recover LNG boil-off gas, a lot of porous materials are needed, and the large-capacity container which accommodates it is needed. In addition, since the pressure of the gas released from the adsorbent-filled container is low, a high pressure booster is indispensable for delivery to a city gas main pipeline or the like.

  Further, (c) Japanese Patent Application Laid-Open No. 8-219397 discloses a technique for adsorbing LNG boil-off gas with an adsorbent. FIG. 11 is a diagram shown in the publication. An adsorption tank 32 containing the LNG storage container 31 and the adsorbent 33 is connected by a pipe (BOG outflow pipe) 35. BOG from the LNG storage container 31 is adsorbed by the adsorbent 33, and the BOG treated with the adsorbent 33 flows out to the catalytic combustion apparatus through the pipe 43 and is burned. As described above, since this technique burns the BOG adsorbed by the adsorbent, it does not recover and effectively use the LNG boil-off gas. Further, in such an apparatus configuration, since the adsorption tank 32 is only disposed at the lower part of the LNG storage container, the adsorbent is not sufficiently cooled, so that the adsorption recovery efficiency of the boil-off gas is low. In FIG. 11, 40 is a vacuum heat insulating layer, 41 is a heat insulating material layer, and 36 is a neck portion of the internal space of the storage container 31.

  Further, (d) Japanese Patent Application Laid-Open No. 2002-106791 discloses a technique for storing hydrogen BOG in a carbonyl-containing organic compound such as acetone using a hydrogenation catalyst and sending it out. FIG. 12 is a diagram shown in the publication. BOG generated in the liquid hydrogen tank 52 is introduced into the hydrogen storage tank 55. The hydrogen storage tank 55 contains acetone 56 and is provided with a hydrogenation catalyst layer 57. Hydrogen BOG reacts with acetone by the catalytic action of the hydrogenation catalyst to become isopropyl alcohol (IPA) and is stored in the form of IPA. Hydrogen BOG is decomposed by heating IPA and separated from IPA. Hydrogen BOG decomposed and separated by heating is supplied to the fuel cell 66.

  However, this technique requires a carbonyl-containing organic compound such as acetone and a hydrogenation catalyst, as well as a hydrogen BOG distribution pipe and a glass filter, and its operation is quite complicated due to the chemical reaction involved in the adsorption and desorption of hydrogen BOG. It is. In FIG. 12, 51 is a vacuum tank, 58 is a hydrogen BOG distribution pipe, 60 is a glass filter, and 67 is a heating pipe circulating from the cooling unit 68 of the fuel cell 66.

JP 2000-213697 A JP-A-8-219397 JP 2002-106791 A

  The present invention solves the above-mentioned problems related to the boil-off gas processing of the prior art by utilizing the gas adsorbing capacity change due to the temperature change of the adsorbent. To provide a boil-off gas processing method and processing apparatus that absorbs, collects, and sends out boil-off gas generated from various liquefied gases, and a low-boiling-point liquefied gas transport apparatus that are not required and that are low-cost and space-saving. Objective.

The present invention (1) is a boil-off gas processing method using an adsorbent-filled container. Then, after the boil-off gas is adsorbed and recovered by the cooled adsorbent in the adsorbent-filled container, the boil-off gas is treated by desorbing, increasing the pressure by external heat input, and sending it out.
The present invention (1) is a boil-off gas processing method using an adsorbent-filled container. Then, after the boil-off gas is adsorbed and recovered by the cooled adsorbent, it is desorbed by raising the temperature by external heat input, and the gas in the adsorbent-filled container is pressurized and sent out.

  The present invention (2) is a boil-off gas processing method using an adsorbent-filled container. In addition, a plurality of adsorbent filling containers are provided, and boil-off gas adsorption recovery by the cooled adsorbent in at least one of the plural adsorbent filling containers, and in other adsorbent filling containers The boil-off gas is continuously delivered by alternately performing desorption of the boil-off gas from the adsorbent due to temperature rise by external heat input and delivery by pressure increase.

  The present invention (3) is a boil-off gas processing apparatus using an adsorbent-filled container. Then, after the boil-off gas is adsorbed and collected by the adsorbent cooled by the cooling means, the boil-off gas is desorbed from the adsorbent, and is boosted and sent out. It is characterized by becoming.

  The present invention (4) is a boil-off gas processing apparatus using an adsorbent-filled container. In addition, a plurality of adsorbent filling containers are provided, and boil-off gas adsorption recovery by the cooled adsorbent in at least one of the plural adsorbent filling containers, and in other adsorbent filling containers It is characterized in that the boil-off gas is continuously delivered by alternately performing desorption of the boil-off gas from the adsorbent due to the temperature rise by external heat input and delivery by the pressure increase.

  The present invention (5) is a low boiling point liquefied gas transport device using a heat insulating container. Then, an adsorbent layer is arranged on the inner wall of the heat insulating container, and the boil-off gas of the low boiling point liquefied gas is adsorbed and collected by the adsorbent layer, and the liquefied gas in the heat insulating container is carried out as it is, and the adsorption boil-off by the adsorbent layer is performed. It is characterized in that the gas is desorbed by increasing the temperature by external heat input, the pressure is increased, and the gas is sent out.

  In the present invention, the boil-off gas, which is a low-pressure gas, can be recovered by the cooled adsorbent, and the pressure can be increased by desorbing a large amount of gas only by external heat input. Thereby, boil-off gas can be sent to a required site, without using boosting means such as an electric booster. In addition, since the boil-off gas is usually a low-pressure gas, an electric booster is currently used, which is costly. However, according to the present invention, the adsorption capacity is reduced to room temperature by cooling the adsorbent. A large amount of boil-off gas can be recovered with a small volume of adsorbent because it improves dramatically over time. Thereby, space saving and cost reduction can be achieved.

  Further, since the adsorbent requires a small amount and a small volume due to high-efficiency recovery of the boil-off gas, a small amount of refrigerant is sufficient to cool the adsorbent. Furthermore, the heat input from the outside at the time of desorption may be natural heat input, exhaust heat such as nitrogen or air discharged from an internal combustion engine or the like, or an external heat source such as an electric heater can be used. Thereby, it can send out without requiring high energy like the past. In addition, by controlling the heat input temperature and the adsorbent filling amount regardless of the gas type, the range of pressure increase due to heat input can be widened.

Examples of the adsorbent of the present invention include activated carbon, metal-supported activated carbon, carbon fiber, charcoal, zeolite, cation ion-exchanged zeolite, zeolite having a metal supported on the zeolite, metal complex (coordination polymer), or metal polyoxide. For example, a porous material having pores is used. The specific surface area is preferably in the range of 100 to 3000 m ² / g, more preferably 1500 to 3000 m ² / g. Activated carbon is used to carbonize mineral raw materials such as petroleum pitch, coal and coke, plant raw materials such as fruit shells such as wood and coconut shells, or yeasts which are a kind of microorganisms, or to activate them further. However, any of these activated carbons can be used in the present invention.

There are natural and synthetic zeolites such as mordenite, A-type zeolite, faujasite (X-type and Y-type zeolite), L-type zeolite, β-type zeolite, ZSM-5, etc. Any one of these zeolites can be used. These zeolites may be those obtained by ion exchange of cations. In this case, an aqueous solution is formed in the form of a metal hydroxide or a salt such as nitrate or acetate, and ion exchange is performed on the zeolite. The cation may be H ⁺ or NH ₄ ⁺ .

  Further, activated carbon and zeolite may be those carrying a metal. Supported metals include Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, La, Ce, Ti, Zr, V, Nb, Cr, Mo, W, Mn, Fe, Ru, Co, Rh Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Al, Ga, In, Si, Ge, Sn, Pb, P, Bi, or the like can be used. Of these, Li, K, Cs, Mg, Ce, Ti, Fe, Ru, Co, Ir, Ni, Pd, Pt, and Ag are preferably used.

  These metals can be supported by dissolving or suspending them in water or an organic solvent in the form of a salt such as nitrate or acetate, impregnating the solution or slurry with activated carbon or zeolite, and then drying.

A metal complex (coordinating polymer) is a porous complex having a structure ranging from 1 to 3 by coordination bonding to two or more metal ions to which multidentate coordination is linked. For example, [CuSiF ₆ (4,4-bipyridine) _{2! n, [Zn 2 (p- (OOC-Ph} -COO)) 2 ! _{n, [Zn 4 (O) p- (OOC} -Ph-COO)) 3 ] _n, [Cu ₂ (pzdc) ₂ (L)] n (wherein pzdc = pyrazine-2,3-dicarboxylate, L = a pillar ligant), [Cu ₃ (1,3,5-C ₆ H ₃ (COOH) ₃ ) ₂ ] _{n and the} like.

The metal polyoxide is composed of transition metal ions such as vanadium (V ⁵⁺ ), molybdenum (Mo ⁵⁺ ), tungsten (W ⁶⁺ ), tantalum (Ta ⁵⁺ ) and oxide ions (O ²⁻ ) of 4 to It is a porous material having a polynuclear complex structure in which a polyhedron such as a tetrahedron, a quadrangular pyramid, an octahedron, etc. formed by coordination of six is a basic unit and a large number of these polyhedrons are condensed. Examples of the basic unit of the polynuclear complex structure are [V ₁₈ O ₄₄ (N ₃ )] ^n- (wherein N ₃ = azide ion (N ₃ ⁻ ), [Mo ₆ O ₁₉ ] ²⁻ , [W ₁₀ O ₃₂ ] ^4- , [Ta ₆ O ₁₉ ] ^2- , etc. Since these are anions, protons (H ⁺ ), Na ⁺ , K ⁺ , Ca ²⁺ , Sr ^2+, etc. Surrounded by cations and also contains molecules such as water molecules.

  In the present invention, it is important that the boil-off gas generated from various low-temperature liquefied gases be adsorbed and recovered by “cooled adsorbent”. The cooling temperature of the adsorbent is more preferably a low temperature close to the boiling point of the boil-off gas (that is, the gas to be treated in the present invention). The adsorbent cooling means is not particularly limited, and any appropriate means such as a refrigerant or a freezer can be used. Any refrigerant having a low boiling point can be used, and liquefied helium, liquefied neon, liquefied nitrogen, or the like can be used. Of these, liquefied nitrogen is preferable because it is inert and inexpensive.

  The low-temperature liquefied gas targeted in the present invention is methane (boiling point = 111.7K), ethane (boiling point = 184.6K), ethylene (boiling point = 169.3K), propane (boiling point = 231.1K), propylene (boiling point). = 226.2K), normal butane (boiling point = 272.7K), isobutane (boiling point = 261.5K), hydrogen (boiling point = 19.3K), carbon dioxide (boiling point = 194.2K), nitrogen (boiling point = 77.K). Liquefied gas of low boiling point gas such as 4K). In particular, a low-temperature liquefied gas having a boiling point of 273 K or less is preferable, and a low-boiling liquefied gas having a boiling point of 200 K or less is more preferable.

  The liquefied gas targeted in the present invention may be a liquefied gas containing a plurality of these low-boiling gases. As an example, natural gas is mainly composed of methane. However, hydrocarbons such as ethane, propane, and butane are heavier than methane, especially in petroleum-based natural gas and structural natural gas, depending on the production area. It is included. As an example, the composition of natural gas is methane = 90.38% (mol%, hereinafter the same), ethane = 4.55%, propane = 3.31%, i-butane = 0.73%, n-butane = 0 94%, i-pentane = 0.03%, n-pentane = 0.01%. Natural gas is stored in the tank as LNG. Since methane and ethane, which are light hydrocarbons, evaporate early from LNG, the boil-off gas from the LNG tank contains many of these light hydrocarbons, especially methane. include.

  In the present invention, the boil-off gas from the low-temperature liquefied gas is adsorbed and recovered by the “cooled adsorbent”, and then “the boil-off gas is desorbed (desorbed) from the adsorbent and raised in pressure by the external heat input”. is important. The boil-off gas is desorbed from the adsorbent as the temperature rises, and the pressure is increased by the desorbed boil-off gas. This “boost” is an important phenomenon used in the present invention. The heat source of external heat input may be natural heat input from outside, that is, natural heat from the atmosphere surrounding the adsorbent filling container, exhaust heat of nitrogen or air discharged from an internal combustion engine, etc., or an electric heater, etc. The external heat source can be used. As described above, in the present invention, the adsorption boil-off gas is desorbed, boosted and sent without requiring expensive energy.

  Incidentally, the above-mentioned Japanese Patent Laid-Open No. 8-219397 discloses a technique for adsorbing LNG boil-off gas to an adsorbent, and it is possible to increase the adsorption capacity by cooling the adsorbent (see paragraph 0015 of the same publication). ). However, in this technique, the LNG boil-off gas adsorbed by the adsorbent is burned, and the LNG boil-off gas is not recovered and effectively used. Further, in the apparatus configuration of the publication, since the adsorption tank is only arranged at the lower part of the LNG storage container, the adsorbent is not sufficiently cooled, so that the adsorption recovery efficiency is low. On the other hand, in the present invention, the adsorbent is sufficiently cooled to adsorb and recover the boil-off gas, and at that time, the boil-off gas is “pressure-raised” by external heat input and effectively used. However, it is fundamentally different from the publication in terms of technical thought.

  Japanese Patent Laid-Open No. 11-57372 discloses gasoline vapor, benzene, toluene, MEK, which is generated in facilities for unloading and unloading volatile hydrocarbons to oil tanks and the like, and facilities for handling solvents such as painting and printing. A method of recovering gaseous hydrocarbons (gaseous hydrocarbons causing photochemical smog) contained in waste gas containing ethyl acetate by an adsorption method is disclosed. In this recovery method, the gaseous hydrocarbon adsorbed in the adsorption tower is cooled to room temperature (about 10 to 30 ° C.), the condensate is collected in the liquid storage container, and the uncondensed gas is returned to the adsorption tower and adsorbed. Is repeated to increase the concentration of gaseous hydrocarbons to be desorbed. Therefore, this recovery method does not adsorb and recover the boil-off gas by the “cooled adsorbent”, which is essential in the present invention.

Japanese Patent Laid-Open No. 11-57372

<Temperature-dependent characteristics of methane adsorption performance>
The embodiment of the present invention will be described in more detail. FIG. 1 is a graph showing temperature-dependent characteristics of methane adsorption performance when the adsorbent is activated carbon (coconut shell activated carbon, specific surface area = 2042 m ² / g). FIG. 2 is an enlarged view of a portion at a temperature of 100 to 300 K in FIG. This data uses the measuring device shown in FIG. 3 (a), and the amount of methane adsorbed when the adsorbent is cooled and the gas is adsorbed by the order and steps shown in FIGS. 3 (b) to 3 (c). Is measured. In FIG. 3A, P ₁ is a vacuum pump, and V _{1 to} V ₆ are on-off valves arranged in each conduit.

In FIG. 3, the container 2 filled with the adsorbent is immersed in a refrigerant (temperature: each temperature in the range of 77 to 298K) and evacuated (step 1). Here, liquid nitrogen was used as the refrigerant. Then, methane gas is introduce | transduced at each pressure of 0.1-1.0 MPa, and methane gas is made to adsorb | suck to an adsorbent (process 2). The adsorbent filling container 1 is closed with V ₆ and taken out from the refrigerant. With the V ₆ closed, the adsorbent filling container 1 is heated to 298 K by external heat. During this time, V ₁ is closed and the vacuum pump P ₁ is in operation, so the inside of the piping is in a vacuum state (step 3). V ₃ is closed, V ₆ is opened, and the amount of gas released from the adsorbent-filled container 1 is measured with an integrated flow meter (step 4). V ₂ is open and all the released gas passes through the integrating flow meter and is measured here.

As shown in FIGS. 1 and 2, at 133 K and 0.1 MPa, 260 times as much methane as the adsorbent-filled container volume 1 (Vvessel) can be stored. Since the amount of adsorption at 1.0 MPa and 298K is 50 times the volume of the adsorbent filled container, in the process of adsorbing at 133K and 0.1 MPa and delivering at 298K and 1.0 MPa, the adsorbent filled container volume is 210. Double boil-off gas can be processed. Further, the internal pressure of the container is increased to 21.4 MPa by raising the temperature to 298 K by external heat input. When the amount of LNG boil-off gas generated is 4000 m ³ / h and the gas delivery pressure is 0.1 MPa, a container having a volume of 19 m ³ may be used to adsorb the boil-off gas generated in one hour. It will be.

<Aspect applied to boil-off gas recovery from a liquefied gas tank such as LNG (Part 1)>
FIG. 4 is a diagram for explaining an example (part 1) in which the present invention is applied to boil-off gas recovery from a liquefied gas tank such as LNG. FIG. 4A shows an example of the apparatus configuration, and FIG. 4B shows the operation process. The pump P ₁ is always operating, and the liquefied gas line is always in a state of flow. The LNG in the liquefied gas tank 1 is vaporized by the vaporizer 2 and then supplied to the city gas main pipeline 3 or used as fuel for a natural gas vehicle. An adsorbent filling container is accommodated in the tank 1.

In FIG. 4 (a), (1) liquefying the liquefied gas in the pump P ₁ from the gas tank 1 in the liquefied gas tank 1 and supplied to the tank 1, to cool the adsorbent of the adsorbent-packed containers accommodated in the tank 1 deep. Then, (2) boil-off gas generated from the liquefied gas tank 1 is introduced into the adsorbent filling container [step 1 in FIG. 4B]. (3) When the adsorption of the boil-off gas to the adsorbent in the adsorbent filling container becomes saturated, the liquefied gas in the tank 1 is discharged to the liquefied gas line by the pump P ₂ in the tank 1. Since the pump P ₁ is always operating and the liquefied gas line is always in a flow state, the pump P ₂ is a pump having a discharge pressure equal to or higher than the discharge pressure of the pump P ₁ . (4) After the discharge of the liquefied gas in the tank 1 is completed, the temperature of the adsorbent-filled container and the tank 1 is increased by performing indirect heat exchange with a heat source. Nitrogen or instrument air heated by steam from various factories is used as the heat source.

(5) As the temperature of the adsorbent filling container rises, the boil-off gas is desorbed from the adsorbent, and the pressure in the adsorbent filling container rises. Therefore, by opening V ₂ , the boil-off gas recovered in the adsorbent-filled container is sent to the recovery line [step 2 in FIG. 4B]. Since the pressure rise in the adsorbent filling container is large, not only the medium-pressure main pipeline 3 such as city gas but also the high-pressure main pipeline 3 can be sent and delivered. (6) Since the residual liquefied gas in the tank 1 is boiled off gas and the pressure in the tank 1 increases, V ₅ is opened to equalize the pressure of the boil off gas line. (7) When the delivery is completed, the liquefied gas is supplied from the liquefied gas tank 1 to the tank 1 to cool the adsorbent in the adsorbent-filled container, and then boil-off gas is introduced. By repeating step 1 and step 2 in this manner, boil-off gas can be adsorbed and recovered and pressurized and sent out.

<Aspect (Part 2) applied to boil-off gas recovery from a liquefied gas tank such as LNG>
FIG. 5 is a diagram for explaining an example (No. 2) applied to boil-off gas recovery from a liquefied gas tank such as LNG. Fig.5 (a) shows the example of an apparatus structure, FIG.5 (b) has shown the operation process. The LNG in the LNG tank 1 is vaporized by the vaporizer 2 and then supplied to the city gas main pipeline 3 or used as fuel for a natural gas vehicle. In this embodiment, two adsorbent filling containers, namely the adsorbent filling container 1 and the adsorbent filling container 2, are used. Adsorbent filling containers 1 and 2 are accommodated in tanks 1 and 2, respectively.

5A, (1) the liquefied gas is supplied from the liquefied gas tank 1 to the tank 1 by the pump P ₁ in the liquefied gas tank 1, and the adsorbent in the adsorbent-filled container 1 is cooled. (2) The boil-off gas generated from the liquefied gas tank 1 is introduced into the adsorbent filling container 1 [step 1 in FIG. 5B]. (3) When the adsorption of the boil-off gas to the adsorbent in the adsorbent filling container 1 becomes saturated, the liquefied gas in the tank 1 is discharged to the liquefied gas line by the pump P ₂ in the tank 1. (4) After the discharge of the liquefied gas in the tank 1 is completed, the adsorbent filling container 1 and the tank 1 are indirectly heat-exchanged with a heat source to raise the temperature. Nitrogen or instrument air heated by factory steam is used as the heat source.

(5) As the temperature of the adsorbent filling container 1 rises, the pressure in the adsorbent filling container 1 increases due to the desorption of the boil-off gas from the adsorbent. Therefore the BOG adsorbed recovered adsorbent filling container 1 by opening the V _7, is sent to the BOG recovery line. Since the pressure rise in the adsorbent filling container 1 is large, not only the medium-pressure main pipeline but also the high-pressure main pipeline can be sent out and delivered. (6) Since the residual liquefied gas in the tank 1 is converted into boil-off gas and the pressure in the tank 1 increases, V ₉ is opened to equalize the pressure of the boil-off gas line [the process 2 in FIG. ].

On the other hand, (1) ′ to (6) ′ are performed while performing the steps (3) to (6). (1) The liquefied gas is supplied from the liquefied gas tank 1 to the tank 2 by the pump P ₁ , and the adsorbent in the adsorbent-filled container 2 is cooled. (2) 'Boil-off gas generated from the liquefied gas tank 1 is introduced into the adsorbent filling container 2 [step 1 in FIG. 5B]. (3) 'When turned adsorption saturation of BOG to the adsorbent in the adsorbent-packed containers 2, it pays out the liquefied gas line liquefied gas in the tank 2 by pump P ₃ in the tank 2. (4) After the liquefied gas discharge in the tank 2 is completed, the adsorbent filling container 2 and the tank 2 are indirectly heat-exchanged with a heat source to raise the temperature. Nitrogen or instrument air heated by factory steam is used as the heat source. (5) As the temperature of the adsorbent filling container 2 rises, the pressure in the adsorbent filling container 2 increases due to the desorption of the boil-off gas from the adsorbent. Therefore, the delivered BOG recovered the adsorbent filling container 2 by opening the V ₈ to BOG recovery line. Since the pressure rise in the adsorbent filling container 2 is large, not only the medium-pressure main pipeline but also the high-pressure main pipeline can be sent out and delivered. (6) 'Since the residual liquefied gas in the tank 2 is boiled off gas and the pressure in the tank 2 rises, V ₁₀ is opened to equalize the pressure of the boil off gas line [the process of FIG. 2].

  In this way, by repeating Step 1 and Step 2 for the tanks 1 and 2 and the adsorbent filling containers 1 and 2, the boil-off gas can be continuously collected and sent out. This embodiment is a case where two adsorbent-filled containers are used, but a plurality of adsorbent-filled containers can be used, and boil-off gas can be continuously collected and delivered in the same manner as described above.

<Temperature-dependent characteristics of hydrogen adsorption performance>
FIG. 6 is a graph showing the temperature dependence characteristics of hydrogen adsorption performance when the adsorbent is activated carbon (coconut shell activated carbon, specific surface area = 1905 m ² / g). This uses the measuring device shown in FIG. 3 (a) and measures the amount of adsorption when the adsorbent is cooled and the gas is adsorbed by the sequence and steps shown in FIGS. 3 (b) to 3 (c). It is a thing. In FIG. 6, the vertical axis represents the hydrogen storage amount (V _H2 ) in the adsorbent relative to the adsorbent-filled container volume (Vvessel).

As shown in FIG. 6, the lower the temperature and the lower the pressure, the greater the degree of increase in the hydrogen storage amount relative to the hydrogen storage amount at room temperature (298 K). At 0.1 MPa and 77 K, 96 times as much hydrogen as the adsorbent-filled container volume 1 (Vvessel) can be stored. Since the adsorption storage amount at 1.0 MPa and 298 K is 12 times the adsorbent filling container volume, in the process of adsorbing at 0.1 MPa and 77 K and sending out at 298 K and 1.0 MPa, the adsorbent filling container volume 84 times the boil-off gas can be processed. Further, when the amount of boil-off gas generated from the liquid hydrogen tank is, for example, 4000 m ³ / h and the gas delivery pressure is 0.1 MPa, a container with a volume of 48 m ³ may be used. When heated, the pressure can be increased to 9.8 MPa.

<Hydrogen adsorption performance depending on cooling of adsorbent>
In addition, using the measuring device shown in FIG. 3A, the hydrogen adsorption performance depending on whether the adsorbent is cooled or the introduced hydrogen is cooled according to the order and steps shown in FIGS. 3B to 3C. did. In FIG. 3A, in the test in which the adsorbent was not cooled, the container 2 was tested without containing liquefied nitrogen. Further, in the test in which the introduced hydrogen was cooled, in FIG. 3A, a test was conducted by placing a cooler with liquefied nitrogen in a pipe following the valve V ₆ from the position of the pressure gauge.

As a result, (1) when hydrogen is introduced without cooling, the V _H2 / Vvessel ratio is 12.5 at an adsorbent temperature of 298K and a hydrogen introduction pressure of 1.0 MPa, and (2) hydrogen is liquid nitrogen at 77K. When cooled and introduced, the V _H2 / Vvessel ratio at an adsorbent temperature of 298 K and a hydrogen introduction pressure of 1.0 MPa is 13.5. (3) The adsorbent is cooled with liquid nitrogen and not cooled to this. Was introduced, the V _H2 / Vvessel ratio at an adsorbent temperature of 77 K and a hydrogen introduction pressure of 1.0 MPa was 167. Thus, it is clear that hydrogen can be adsorbed very effectively by using a precooled adsorbent. Moreover, even if cooled hydrogen is introduced into an adsorbent that has not been cooled in advance, the adsorption performance is only slightly improved compared to when hydrogen at room temperature is introduced.

<Temperature-dependent characteristics of carbon dioxide adsorption performance>
FIG. 7 is a graph showing temperature-dependent characteristics of carbon dioxide adsorption performance when the adsorbent is activated carbon (coconut shell activated carbon, specific surface area = 1035 m ² / g). This uses the measuring device shown in FIG. 3 (a) and measures the amount of adsorption when the adsorbent is cooled and the gas is adsorbed by the sequence and steps shown in FIGS. 3 (b) to 3 (c). It is a thing. In FIG. 7, the vertical axis represents the carbon dioxide storage amount (Vco ₂ ) in the adsorbent with respect to the adsorbent-filled container volume (Vvessel).

  Although FIG. 7 shows the storage amount (container volume ratio) when carbon dioxide is adsorbed at an introduction pressure of 4 MPa, the lower the temperature, the larger the carbon dioxide storage amount. As shown in FIG. 7, carbon dioxide boil-off gas that is 590 times as large as the adsorbent-filled container volume 1 (Vvessel) is stored at 200K. The amount of carbon dioxide boil-off gas adsorption at 298K is 150 times the adsorbent-filled container volume. Therefore, in the process of adsorbing carbon dioxide boil-off gas at 200K and sending it out at 298K, it is possible to treat carbon dioxide boil-off gas 440 times the adsorbent filling container volume after subtracting the adsorption amount at the discharge pressure at 298K. become.

  As described above, the boil-off gas from the liquid hydrogen tank and the boil-off gas from the liquid carbon dioxide tank are also used in the same manner as in the above-described <applied mode for recovering boil-off gas from a liquefied gas tank such as LNG (part 1)>. The boil-off gas can be collected and sent out in the same manner as in <Aspect (Part 2) applied to boil-off gas recovery from a liquefied gas tank such as LNG> (2)>.

<Mode of transportation device for low boiling point liquefied gas by heat insulating container>
FIG. 8 is a diagram for explaining a mode example of a transport device that transports hydrocarbons such as hydrogen and methane, or low-boiling-point liquefied gas such as natural gas with a heat insulating container, using a lorry vehicle or the like. As shown in FIG. 8, the adsorbent layer 5 is disposed on the inner wall of the heat insulating container 4, that is, the inner peripheral side thereof. Then, the boil-off gas generated from the liquefied gas stored in the heat insulating container 4 is adsorbed and recovered by the adsorbent layer 5. In FIG. 8, 6 is a supply / delivery pipe for liquefied gas, and 7 is an on-off valve. In this aspect, since the adsorbent layer 5 is disposed on the inner periphery of the heat insulating container 4, it also has a heat insulating effect and can insulate the liquefied gas more effectively.

  Since the adsorbent layer 5 is cooled by the liquefied gas accommodated in the heat insulating container 4, the boil-off gas is adsorbed and recovered by the cooled adsorbent without requiring a separate cooling means. The cooled adsorbent layer 5 adsorbs the boil-off gas from the low boiling point liquefied gas with high efficiency and suppresses the pressure increase in the heat insulating container 4. After such a transport device is transferred to a destination by an automobile, a freight car, a ship, etc., the liquefied gas in the heat insulating container 4 is carried out as it is. That is, the low boiling point liquefied gas in the heat insulating container 4 can be derived and transferred to a storage tank or the like.

  The boil-off gas, which is a low boiling point liquefied gas, is adsorbed and collected by the adsorbent layer 5 disposed on the inner wall of the heat insulating container 4, but when the heat insulating container 4 is released from the heat insulation, the temperature rises due to external heat input and the boil off is performed. The gas is desorbed from the adsorbent and the pressure is increased. The heat source for external heat input may be natural heat input from the outside, that is, the atmosphere surrounding the heat insulating container, exhaust heat from an internal combustion engine or the like, or an external heat source such as an electric heater. FIG. 8B shows a case where the electric heater 8 is used. Since the desorption gas is pressurized enough to be able to transport the pipe, when the desorption gas is boil-off gas from LNG, for example, it is sent to the high-pressure main pipeline as well as the medium-pressure main pipeline such as city gas, Delivery is also possible.

  The transport amount of the low boiling point liquefied gas transport device by the heat insulating container can be increased by an amount corresponding to the amount adsorbed by the adsorbent layer as compared with the transport amount by the conventional heat insulating container transport device. Further, the pressure-resistant safety of the heat insulating container can be improved by the adsorption of the boil-off gas by the adsorbent layer. Furthermore, it is possible to improve the efficiency of operations such as shortening the unloading time by increasing the pressure of the boil-off gas that has been adsorbed and recovered by the adsorbent layer disposed on the inner wall of the heat insulating container. Thus, according to the heat insulation container of the present invention, various useful effects can be obtained.

Figure showing the temperature-dependent characteristics of methane adsorption performance when the adsorbent is activated carbon The figure which expanded and showed the part of temperature 100-300K among FIG. The figure which shows the measuring device used for the measurement of the temperature dependence characteristic of the gas adsorption performance of the adsorbent The figure explaining the example (the 1) applied to boil-off gas collection | recovery from liquefied gas tanks, such as LNG The figure explaining the example (the 2) applied to boil-off gas collection | recovery from liquefied gas tanks, such as LNG Figure showing the temperature-dependent characteristics of hydrogen adsorption performance when the adsorbent is activated carbon The figure which showed the temperature dependence characteristic of the adsorption performance of carbon dioxide when the adsorbent is activated carbon The figure which shows the example of the aspect of the transport apparatus which transports low boiling point liquefied gas, such as hydrocarbons, such as hydrogen and methane, and natural gas with a heat insulation container, etc. Diagram showing prior art that requires an electric booster The figure which shows the prior art which carries out the adsorption process of LNG boil-off gas with an adsorbent. The figure which shows the prior art which carries out the adsorption process of LNG boil-off gas with an adsorbent. The figure which shows the prior art which occludes and sends out hydrogen BOG

Explanation of symbols

V ₁ ~V ₁₀ off valve P ₁ to P ₃ pump 1 liquefied gas tank 2 vaporizer 3 trunk pipeline 4 insulated container 5 supply pipe and delivery pipe 7 off valve 8 electric heater 11 and 21 LNG tanks adsorbent layer 6 liquefied gas 12 Booster (Compressor)
DESCRIPTION OF SYMBOLS 13 Vaporizer 22 BOG line 24 Adsorption-type BOG holder 23, 25 BOG line before and behind adsorption-type BOG holder 24 26 Pump arrange | positioned at LNG extraction pipe 28 from LNG tank 21 28 LNG extraction pipe 31 LNG storage container 32 Adsorbent Adsorption tank containing 33 35 Piping (BOG outflow pipe)
36 Neck of storage container 31 internal space 40 Vacuum heat insulating layer 41 Heat insulating material layer 43 Piping 51 Vacuum tank,
52 Liquid Hydrogen Tank 55 Hydrogen Storage Tank 56 Acetone 57 Hydrogenation Catalyst Layer 58 Hydrogen BOG Distribution Pipe 60 Glass Filter 67 Heating Tube Circulated from Cooling Unit 68 of Fuel Cell 66

Claims (4)

A transport device of the low-boiling liquefied gas due to adiabatic vessel, said heat insulating container is provided with a supply pipe and the delivery pipe of the low-boiling liquefied gas, and, in insulation container having an adsorbent layer on the entire surface of the inner wall of its There, the heat insulating container BOG low-boiling liquefied gas contained adsorbed recovered, desorbed from the adsorbent layer by an equivalent intake Chakuboiruofugasu raising the temperature by external heat input, boosted by the adsorbent layer The low-boiling-point liquefied gas transporting apparatus is characterized in that the low-boiling-point liquefied gas transport device is configured to deliver the gas via the supply pipe / delivery pipe . 2. The low boiling point liquefied gas transport apparatus according to claim 1 , wherein the adsorbent is activated carbon, metal-supported activated carbon, carbon fiber, charcoal, zeolite, cation ion-exchanged zeolite, zeolite having a metal supported on the zeolite, or metal complex. Alternatively, a low-boiling liquefied gas transport device, which is a metal polyoxide. 3. The low boiling point liquefied gas transport apparatus according to claim 1 , wherein the external heat input is natural heat input from an air atmosphere surrounding a heat insulating container, heat input by exhaust heat from an internal combustion engine, or an electric heater. A low boiling point liquefied gas transport device characterized by being heat input from an external heat source. The low boiling point liquefied gas transport apparatus according to any one of claims 1 to 3 , wherein the low boiling point liquefied gas is liquefied methane, liquefied ethane, liquefied ethylene, liquefied propane, liquefied butane, liquefied natural gas, liquefied hydrogen or A low-boiling point liquefied gas transport device characterized by being liquefied carbon dioxide.

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