Liquefied gas utilization system and vehicle

Abstract

To provide a liquefied gas utilization system that is excellent in utilization efficiency of a liquefied gas, and to provide a vehicle.SOLUTION: A liquefied gas utilization system (100) includes: a storage part (10) for storing a liquefied gas containing a component A; an adjustment part (20) for adjusting the content of the component A contained in the liquefied gas; a vaporization part (30) for converting the liquefied gas into a gas; and a combustion part (40) for combusting the gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a liquefied gas utilization system and a vehicle. [Background technology]

[0002] Liquefied gas obtained by liquefying fuel that is in a gaseous state at room temperature and pressure is widely used as a thermal energy source obtained by vaporizing and burning the liquefied gas (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-89828 Summary of the Invention [Problem to be solved by the invention]

[0004] Liquefied gas is also used as fuel for automobiles. Liquefied gas used as automobile fuel is generally composed mainly of propane and butane. Butane has a lower vapor pressure than propane and is less likely to vaporize at low temperatures. For this reason, liquefied gas with a high butane content may not vaporize sufficiently when the ambient temperature is low or when the engine is not warm when starting a car, which can lead to problems such as over-rich (a condition in which the fuel ratio in the oxygen and fuel mixture supplied to the engine is too high). In view of the above circumstances, an object of the present disclosure is to provide a liquefied gas utilization system and a vehicle that have excellent utilization efficiency of liquefied gas. [Means for solving the problem]

[0005] The means for solving the above problems include the following embodiments. <1> a storage section for storing a liquefied gas containing component A; an adjusting unit that adjusts the content of component A contained in the liquefied gas; a vaporizer that converts the liquefied gas into a gas; A liquefied gas utilization system comprising: a combustion unit that combusts the gas. <2> The adjusting unit adjusts the content of component A in the liquefied gas supplied to the vaporizing unit so that it is greater than the content of component A in the liquefied gas stored in the storage unit. <1> The liquefied gas utilization system described in the above. <3> The adjusting section has a function of separating at least a portion of components other than component A from the liquefied gas. <1> or <2> The liquefied gas utilization system described in the above. <4> Component A is propane or butane; <1> ~ <3> The liquefied gas utilization system according to any one of claims 1 to 10. <5> The control unit includes a metal-organic framework. <1> ~ <4> The liquefied gas utilization system according to any one of claims 1 to 10. <6> The liquefied gas is liquefied petroleum gas. <1> ~ <5> The liquefied gas utilization system according to any one of claims 1 to 10. <7> a refrigerant that cools the combustion section; A control unit that controls the operation of the adjustment unit based on the temperature of the refrigerant. <1> ~ <6> The liquefied gas utilization system according to any one of claims 1 to 10. <8> The control unit operates the adjustment unit when the temperature of the refrigerant at the start of the combustion unit is lower than a first predetermined temperature. <7> The liquefied gas utilization system described in the above. <9> The control unit supplies the liquefied gas having an adjusted content of component A to the vaporization unit when the temperature of the refrigerant after the start of the combustion unit is lower than a second predetermined temperature. <7> or <8> The liquefied gas utilization system described in the above. <10> The control unit does not operate the adjustment unit when the temperature of the refrigerant at the start of the combustion unit is equal to or higher than a first predetermined temperature. <7> ~ <9> The liquefied gas utilization system according to any one of claims 1 to 10. <11> <1> ~ <10> A vehicle equipped with a liquefied gas utilization system according to any one of claims 1 to 4. [Effects of the Invention]

[0006] According to the present disclosure, a liquefied gas utilization system and a vehicle that have excellent utilization efficiency of liquefied gas are provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a liquefied gas utilization system. [Figure 2] 1 is a schematic diagram showing an example of the configuration of a liquefied gas utilization system. [Figure 3] 1 is a schematic diagram showing an example of the configuration of a liquefied gas utilization system. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In this specification, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples.

[0009] One embodiment of the present disclosure comprises: a storage section for storing a liquefied gas containing component A; an adjusting unit that adjusts the content of component A contained in the liquefied gas; a vaporizer that converts the liquefied gas into a gas; and a combustion unit that combusts the gas.

[0010] The liquefied gas utilization system of the present disclosure is equipped with an adjustment unit that adjusts the content of component A contained in the liquefied gas before vaporization. In the present disclosure, "component A" refers to a component contained in the liquefied gas whose content is subject to adjustment by the adjustment unit. The adjustment unit functions, for example, to increase the proportion of a component with a relatively high vapor pressure as component A contained in the liquefied gas. For example, when the liquefied gas before vaporization is a mixed gas of propane and butane, the adjustment unit functions to increase the content of propane as component A contained in the liquefied gas supplied to the vaporization unit. As a result, the liquefied gas can be sufficiently vaporized even when, for example, the temperature is low and the liquefied gas is difficult to vaporize. Each component of the liquefied gas utilization system will be described below.

[0011] (Storage section) The storage unit stores a liquefied gas containing component A. In this disclosure, "liquefied gas" refers to a substance that is in a gaseous state at normal temperature and pressure and that has been liquefied by compression or cooling. The type of liquefied gas is not particularly limited and can be set depending on the application of the internal combustion engine, etc. Examples of liquefied gas include liquefied petroleum gas (LPG) made from petroleum, and liquefied natural gas (LNG) made from natural gas. The types of components contained in the liquefied gas include hydrocarbons having 1 to 4 carbon atoms, such as methane, ethane, propane, butane, etc. From the viewpoint of achieving the effects of the present invention, it is preferable that the liquefied gas contains two or more components having different vapor pressures. Only one of the components contained in the liquefied gas may be component A, or two or more of them may be component A. In one embodiment of the present disclosure, the liquefied gas may contain propane and butane. When the liquefied gas contains propane and butane, the mixing ratio thereof is not particularly limited. For example, the volume ratio of propane to butane (propane:butane) may be within a range of 1:9 to 9:1. The shape of the storage section is not particularly limited, and may be a known shape such as a gas cylinder.

[0012] (Adjustment part) The adjusting unit adjusts the content of component A contained in the liquefied gas. The adjusting unit adjusts, for example, the content of component A contained in the liquefied gas supplied to the vaporizing unit so that it is greater than the content of component A in the liquefied gas contained in the storage unit.

[0013] Component A, the content of which is adjusted by the adjusting section, may be a component that has a relatively high vapor pressure (that is, is easily vaporized) among the components contained in the liquefied gas. When component A whose content is adjusted by the adjusting unit is a component with a relatively high vapor pressure, for example, it can promote vaporization of the liquefied gas while the liquefied gas utilization system is operating in a low-temperature environment.

[0014] Component A, the content of which is adjusted by the adjusting section, may be a component that has a relatively low vapor pressure (that is, is difficult to vaporize) among the components contained in the liquefied gas. If component A, the content of which is adjusted by the adjusting unit, is a component with a relatively low vapor pressure, for example, while the liquefied gas utilization system is operating in an environment in which component A can be vaporized well, component A can be consumed preferentially, and consumption of components with a higher vapor pressure than component A can be reduced.

[0015] The adjustment of the content rate of component A by the adjustment unit may be performed continuously during operation of the liquefied gas utilization system, or may be performed while including rest periods. From the viewpoint of improving the utilization efficiency of the liquefied gas, it is preferable that the adjustment of the content rate of component A by the adjustment unit be performed while including rest periods. A first example of a case in which the adjustment of the content of component A by the adjustment unit is carried out while including a pause period is a case in which the adjustment is carried out for a certain period of time after the start of operation of the liquefied gas utilization system, and then the adjustment is paused. A second example of a case in which the adjustment of the content of component A by the adjustment unit is carried out while including a rest period is a case in which the adjustment is carried out while the temperature of the liquefied gas utilization system or its surroundings does not satisfy a specified condition, and the adjustment is paused while the temperature of the liquefied gas utilization system or its surroundings satisfies the specified condition. The adjusting unit may be provided with a means such as a timer, a thermometer, an electronic control system, etc. for switching between adjustment of the content rate of component A and pause.

[0016] The method for adjusting the content of component A by the adjusting portion is not particularly limited. A first example of a method for adjusting the content of component A using an adjusting section is a method for separating at least a portion of components other than component A contained in the liquefied gas (hereinafter also referred to as component B).

[0017] Separation of component B contained in liquefied gas can be carried out, for example, by using a substance that captures component B more easily than component A. Examples of such substances include substances that have pores that are larger than the molecular size of component A and smaller than the molecular size of component B. When liquefied gas contains propane as component A and butane as component B, the pore size can be calculated, for example, as follows: In the following calculation, the bond length (CH) between a carbon atom and a hydrogen atom is set to 106 pm to 112 pm, and the bond length (CC) between carbon atoms and carbon atoms is set to 120 pm to 154 pm.

[0018] Assuming that the propane molecule (molecular structure: H-CH2-CH2-CH2-H) is linear, the minimum length along its long axis is calculated to be 106 x 2 + 120 x 2 = 452 pm, and the maximum length is calculated to be 112 x 2 + 154 x 2 = 532 pm. Assuming that the butane molecule (molecular structure: H-CH2-CH2-CH2-CH2-H) is linear, the minimum length along its long axis is calculated to be 106 x 2 + 120 x 3 = 572 pm, and the maximum length is calculated to be 112 x 2 + 154 x 3 = 686 pm. From the above results, it is thought that pores with sizes of 532 pm to 572 pm tend to be less likely to trap propane and more likely to trap butane. Note that, since the actual molecular structure of propane or butane is not linear, the length in the major axis direction is smaller than the above calculated value. Therefore, it is thought that the actual size of pores that can selectively trap butane is smaller than the above calculated value.

[0019] The length of the propane and butane molecules in the short axis direction (212 pm to 224 pm) is smaller than the above-mentioned pore size, so depending on the orientation of the molecules, butane may pass through the pores together with propane. However, statistically speaking, it is more difficult for butane to pass through than propane, and it is thought that more butane molecules than propane will be captured by the material with the pores.

[0020] An example of a substance having pores that can capture component B other than component A contained in liquefied gas is a metal organic framework (MOF). MOFs are porous complexes composed of metal ions and organic molecules, and it is known that their pore size can be controlled by the type of raw material and synthesis conditions. Specific examples of metal ions contained in MOFs include Cu, Zn, Co, In, Al, Fe, V, Mg, Mn, Ni, Ru, Mo, Cr, W, Rh, and Pd. Among these, Cu, Zn, Co, In, Al, Fe, and V are preferred, and Cu, Zn, and Co are more preferred. The organic molecules contained in the MOF are not particularly limited as long as they are organic ligands that can form coordinate bonds with metal ions. Specific examples of organic molecules include dicarboxylic acids, tricarboxylic acids, imidazoles, benzimidazoles, azabenzimidazoles, and derivatives thereof. Specific examples of MOFs include Cu-BTC, MOF-5, IRMOF-3, MIL-47, MIL-53, MIL-96, MMOF, SIM-1, ZIF-7, ZIF-8, ZIF-22, ZIF-69, and ZIF-90, but the MOFs used in the present disclosure are not limited to these. The types of metal ions and organic molecules that constitute the MOF are not particularly limited and can be selected depending on the desired pore size, etc. When the adjusting part contains a MOF, the adjusting part may contain only one type of MOF or two or more types of MOFs.

[0021] The liquefied gas utilization system of the present disclosure may include a recovery section that recovers component B separated in the adjustment section. The recovery section recovers component B separated in the adjustment section, for example, when the liquefied gas utilization system starts operating. From the viewpoint of the utilization efficiency of the liquefied gas, it is preferable that the recovery section has a function of supplying the recovered component to the vaporization section. That is, under predetermined conditions (for example, when the temperature of the vaporization section is sufficiently high), component B recovered in the recovery section may be supplied to the vaporization section and converted into gas. By providing a recovery section with such a function, the liquefied gas can be stably vaporized. The recovery section may recover component A together with component B, provided that it recovers at least component B contained in the liquefied gas. In other words, the recovery section may recover only component B, or may recover a mixture of component A and component B (where the proportion of component A is smaller than in the liquefied gas before the components are adjusted in the adjustment section).

[0022] A second example of a method for adjusting the content of component A by the adjusting section is a method in which the mixing ratio of two or more liquefied gases having different contents of component A is adjusted in the adjusting section. For example, a method can be exemplified in which two or more types of liquefied gases with different contents of component A are stored in the storage unit, and the flow rates of the two or more types of liquefied gases are respectively adjusted in the adjustment unit. By relatively increasing the flow rate of the liquefied gas with a higher content of component A supplied from the storage unit in the adjustment unit, the content of component A in the liquefied gas supplied to the vaporization unit can be increased. When two or more liquefied gases having different contents of component A are used in the liquefied gas utilization system of the present disclosure, one of the liquefied gases may not contain component A at all.

[0023] (evaporation section) The vaporizer converts the liquefied gas supplied from the storage unit via the regulator into a gas. The method for converting a liquefied gas into a gas is not particularly limited and can be carried out by a known method. For example, the liquefied gas may be converted into a gas by reducing the pressure applied to the liquefied gas. The shape of the vaporizing section is not particularly limited, and may be a known shape such as a regulator.

[0024] The liquefied gas supplied to the vaporizer has its component ratio adjusted in the adjusting section, so that the vaporization of the liquefied gas can be carried out more stably than, for example, vaporizing the liquefied gas contained in the storage section as is.

[0025] (Combustion section) The combustion section burns the gas obtained by vaporizing the liquid gas in the vaporization section. The form of the combustion section is not particularly limited as long as it is capable of combusting the components contained in the liquefied gas, and can be selected depending on the application of the liquefied gas utilization system. The method of utilizing the energy obtained by burning the components contained in the liquefied gas may be a method of utilizing the thermal energy obtained by burning the components contained in the liquefied gas itself, or a method of converting the thermal energy into mechanical energy, electrical energy, light energy, etc. and utilizing it. The form of the combustion section is not particularly limited, and may be a known form such as an engine (internal combustion engine) or a burner.

[0026] (Control unit) The liquefied gas utilization system of the present disclosure may further include a control unit that controls the operation of the adjustment unit based on the temperature of the refrigerant that cools the combustion unit. The refrigerant for cooling the combustion section can be any refrigerant commonly used in liquefied gas utilization systems, without any particular restrictions. The control section can be, for example, a device with a processing function, such as a computer.

[0027] The control unit may have a function of activating the adjustment unit when the refrigerant temperature at the start of the combustion unit is below a first predetermined temperature. When the control unit has this function, for example, the startability of the combustion unit at low temperatures is improved. As a result, for example, the drivability (running performance) of an automobile equipped with a liquefied gas utilization system can be improved. The control unit may have a function of not operating the adjustment unit when the temperature of the refrigerant at the start of the combustion unit is equal to or higher than a first predetermined temperature. If the control unit has the above function, for example, when there is no need to adjust the content of component A contained in the liquefied gas, the operation of the adjustment unit can be suspended, thereby saving operating costs. In this disclosure, "startup of the combustion unit" refers to a period during which the combustion unit is operating at a minimum rotation speed under no load (idling). The value of the first predetermined temperature is not particularly limited and can be set depending on the type of liquefied gas utilization system, the usage environment, etc. For example, the first predetermined temperature may be selected from the range of 0°C to 15°C, or may be 10°C.

[0028] The control unit may have a function of supplying the liquefied gas having an adjusted content of component A to the vaporization unit when the temperature of the refrigerant after the combustion unit is started is lower than a second predetermined temperature. When the control unit has the above function, for example, a component that has a relatively high vapor pressure and is easily vaporized (e.g., propane) separated from the liquefied gas by the adjustment unit can be selectively used as fuel for the combustion unit in a state of low combustion efficiency. The control unit may have a function of supplying components other than component A separated from the liquefied gas to the vaporization unit when the temperature of the refrigerant after the combustion unit is started is equal to or higher than a second predetermined temperature. When the control unit has the above function, for example, a component (e.g., butane) that has a relatively low vapor pressure and is difficult to vaporize and that is separated from the liquefied gas by the adjustment unit can be selectively used as fuel for the combustion unit in a state of high combustion efficiency. The value of the second predetermined temperature is not particularly limited and can be set depending on the type of liquefied gas utilization system, the usage environment, etc. For example, the second predetermined temperature may be selected from the range of 20°C to 35°C, or may be 30°C.

[0029] (Applications of liquefied gas utilization systems) Specific applications of liquefied gas utilization systems include automobiles, ships, aircraft, chainsaws, brush cutters, generators, water heaters, air conditioners, gas cookers, and gas stoves. The liquefied gas utilization system of the present disclosure is particularly effective when the liquefied gas contains propane and butane. Liquefied gas containing propane and butane is used in automobiles. Liquefied gas distributed as automobile fuel is mainly a mixture of propane and butane, and the mixture ratio varies depending on the region and season. For example, liquefied gas distributed in warm regions or seasons has a higher proportion of butane than liquefied gas distributed in cold regions or seasons. In other words, the utilization efficiency of liquefied gas containing propane and butane is easily affected by temperature conditions. Therefore, a suitable example of an application of the liquefied gas utilization system of the present disclosure is an automobile engine. That is, one embodiment of the present disclosure is an automobile including the liquefied gas utilization system of the present disclosure. In the present disclosure, automobiles include automobiles for transporting people and goods, as well as industrial automobiles such as forklifts and tractors. The liquefied gas utilization system of the present disclosure may also use energy sources other than liquefied gas, such as gasoline, kerosene, or electricity.

[0030] (Example of a liquefied gas system configuration) The liquefied gas utilization system of the present disclosure will be described below with reference to the drawings. FIG. 1 is a diagram schematically illustrating an example of the configuration of a liquefied gas utilization system according to the present disclosure. As shown in Figure 1, the liquefied gas utilization system 100 includes a storage unit 10 for storing liquefied gas, an adjustment unit 20 for adjusting the content of component A contained in the liquefied gas, a vaporization unit 30 for converting the liquefied gas into a gas, and a combustion unit 40 for combusting the gas converted from the liquefied gas. The storage unit 10 and the adjustment unit 20 are connected by a transfer path 50 for transferring the liquefied gas in a liquid state. The adjusting unit 20 and the vaporizing unit 30 are connected by a transfer path 60 for transferring the liquefied gas in a liquid state. The vaporizing section 30 and the combustion section 40 are connected by a transfer path 70 for transferring the liquefied gas in a gaseous state. When the adjusting unit 20 adjusts the component A contained in the liquefied gas, the liquefied gas transferred through the transfer path 60 has a different content of component A from the liquefied gas transferred through the transfer path 50. When the adjusting unit 20 is not adjusting the component A contained in the liquefied gas, the liquefied gas transferred through the transfer path 60 has the same content of component A as the liquefied gas transferred through the transfer path 50.

[0031] Fig. 2 shows an example of the configuration of the liquefied gas utilization system 100 shown in Fig. 1. In Fig. 2, the adjustment unit 20 includes a separation unit 20A that separates component B other than component A contained in the liquefied gas, and a recovery unit 20B that recovers component B separated from the liquefied gas. Separation unit 20A is connected to recovery unit 20B by a transfer path 80 for transferring component B separated from the liquefied gas. Recovery unit 20B is connected to a transfer path 60 that connects the adjustment unit 20 and the vaporization unit 30 by a transfer path 90 for transferring the recovered component B to the vaporization unit 30. The transfer path 90 may be connected to the transfer path 60 as shown in FIG. 2, or may be independent of the transfer path 60 and connect the recovery unit 20B and the vaporization unit 30.

[0032] Fig. 3 shows an example of the configuration of the liquefied gas utilization system 100 shown in Fig. 1. In Fig. 3, the storage unit 10 includes storage units 10A and 10B. Storage units 10A and 10B store liquefied gases having different contents of component A, respectively, and are connected to the adjustment unit 20 by independent transfer paths 50A and 50B. The adjustment unit 20 adjusts the content of component A contained in the liquefied gas supplied to the vaporization unit 30 by adjusting the flow rate of the liquefied gas supplied from the transfer paths 50A and 50B.

[0033] The configuration of the liquefied gas utilization system 100 shown in each figure can be modified without departing from the gist of the present disclosure. For example, the transfer path 70 connecting the vaporization unit 30 and the combustion unit 40 shown in each figure may be one, as shown in Figures 1 to 3, or a combination of two or more (for example, a combination of a transfer path including an adapter and a transfer path including an injector). The liquefied gas utilization system 100 may further include a temperature adjustment unit (not shown) for adjusting the temperature of the vaporization unit 30. This temperature adjustment unit may use a refrigerant to cool the combustion unit 40. [Explanation of symbols]

[0034] 10 Storage Unit 20 Adjustment part 30 Vaporization section 40 Combustion section 50, 60, 70, 80, 90 transfer path 100 Liquefied gas utilization system

Claims

1. a storage section for storing a liquefied gas containing component A; an adjusting unit for adjusting the content of component A contained in the liquefied gas; a vaporizer that converts the liquefied gas into a gas; A liquefied gas utilization system comprising: a combustion unit that combusts the gas.

2. The liquefied gas utilization system according to claim 1, wherein the adjustment unit adjusts the content of component A in the liquefied gas supplied to the vaporization unit so that it is greater than the content of component A in the liquefied gas stored in the storage unit.

3. The liquefied gas utilization system according to claim 1, wherein the adjusting section has a function of separating at least a portion of components other than component A from the liquefied gas.

4. 2. The liquefied gas utilization system according to claim 1, wherein component A is propane or butane.

5. The liquefied gas utilization system according to claim 1 , wherein the regulator includes a metal-organic framework.

6. The liquefied gas utilization system according to claim 1 , wherein the liquefied gas is liquefied petroleum gas.

7. a refrigerant that cools the combustion section; The liquefied gas utilization system according to claim 1 , further comprising: a control unit that controls the operation of the adjustment unit based on the temperature of the refrigerant.

8. The liquefied gas utilization system according to claim 7 , wherein the control unit operates the adjustment unit when the temperature of the refrigerant at the start of the combustion unit is lower than a first predetermined temperature.

9. The liquefied gas utilization system described in claim 7, wherein the control unit supplies liquefied gas having an adjusted content of component A to the vaporization unit when the temperature of the refrigerant after startup of the combustion unit is less than a second predetermined temperature.

10. The liquefied gas utilization system according to claim 7 , wherein the control unit does not operate the adjustment unit when the temperature of the refrigerant at the start of the combustion unit is equal to or higher than a first predetermined temperature.

11. A vehicle equipped with the liquefied gas utilization system according to any one of claims 1 to 10.

Images