JP4649028B2 - Method for vaporizing water-insoluble liquid fuel used in fuel cell system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for vaporizing a water-insoluble liquid fuel used in a fuel cell system or the like.
[0002]
[Prior art]
Conventionally, in this type, as disclosed in, for example, JP-A-5-283091, liquid fuel and water are separately vaporized and then led to a reformer and mixed to perform steam reforming. I was going to go.
[0003]
[Problems to be solved by the invention]
By the way, in this conventional device, the vaporization temperature in the fuel vaporizer needs to be kept higher than the vaporization temperature of the liquid fuel in order to obtain the reliable vaporization of the liquid fuel. Therefore, a liquid having a relatively high vaporization temperature such as kerosene. In the case of fuel, if the vaporization temperature in the vaporizer is increased in order to completely vaporize the liquid fuel, there is a possibility that kerosene, which is the liquid fuel, is vaporized and thermally decomposed at a high temperature before being mixed with water vapor.
[0004]
Also, in order to prevent thermal decomposition of liquid fuel due to high temperature, if the vaporization temperature in the fuel vaporizer is set close to the vaporization temperature of the liquid fuel, the liquid fuel may not be sufficiently vaporized due to variations in the quality of the liquid fuel. There is also a problem that components having a high target vaporization temperature accumulate in the fuel vaporizer.
[0005]
[Means for Solving the Problems]
This invention pays attention to this point, and in order to solve the above-mentioned drawbacks, in particular, its structure is composed of a water vaporizer that vaporizes water alone to form water vapor, and a fuel vaporizer that has a heat source and heats liquid fuel to vaporize it. The vaporization temperature of the liquid fuel is supplied by supplying the liquid vapor to the fuel vaporizer when the vaporization vaporized by the water vaporizer is supplied to the fuel vaporizer and the fuel vaporizer is filled with the vapor. It is configured to decrease.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The liquid fuel is sprayed into the fuel vaporizer 5 constituting the water vapor mixing means heated to a predetermined temperature by a heat source such as the vaporization heater 1a, and the vapor vaporized in advance in the water vaporizer 1 is determined by the amount of the fuel to be sprayed. A predetermined amount is supplied and the liquid fuel is vaporized while being mixed in the fuel vaporizer 5.
[0010]
At this time, since the vapor phase portion in the fuel vaporizer 5 is in a state where the water vapor and the liquid fuel vapor are mixed, the vapor pressure of the liquid fuel vapor is lower than the atmospheric pressure, and the liquid fuel is heated and vaporized alone. It can be vaporized at a lower temperature than
[0011]
Therefore, the predetermined temperature can be set lower than the case where the liquid fuel is heated and vaporized alone, and the thermal decomposition of the liquid fuel due to the high temperature can be prevented.
[0012]
Further, even when the predetermined temperature is set to be relatively low, the vapor pressure of the liquid fuel vapor is low, so that the liquid fuel can be sufficiently vaporized, and the component having a relatively high vaporization temperature cannot be completely vaporized. There is no problem of accumulating.
[0013]
Therefore, even when liquid fuel with a relatively high vaporization temperature, such as kerosene, is vaporized, there is no thermal decomposition due to high temperatures, and even if there is a variation in the quality of the liquid fuel, it can be vaporized reliably. is there.
[0014]
【Example】
Next, a vaporizing method according to the present invention will be described with reference to an embodiment shown in the drawings.
Reference numeral 1 denotes a water vaporizer using a heater 1 a as a heat source, which generates water vapor by appropriately supplying water stored in a water tank 2 through a water pump 3. Is provided.
[0015]
Reference numeral 5 denotes an aluminum die-cast fuel vaporizer in which a vaporization heater 5a is cast at a lower portion, and a water vapor outlet 5b for blowing water vapor from the water vaporizer 1 communicates with one side, and a fuel is supplied to the jet outlet 5b. A nozzle 5c that sprays liquid fuel is provided in communication with a fuel pump 7 that supplies fuel in the tank 6, and heats and vaporizes the liquid fuel while mixing water vapor.
[0016]
A burner fuel pump 8 supplies fuel to a reformer heating burner (not shown) in the reformer 9.
[0017]
Next, the operation of this embodiment will be described.
When the vaporization heater 5a is energized and the fuel vaporizer 5 is heated to reach a predetermined temperature suitable for vaporization of the liquid fuel, the vapor vaporized in the water vaporizer 1 from the water tank 2 via the water pump 3 is vaporized. The fuel carburetor 5 is supplied from the outlet 5b, and the air in the fuel carburetor 5 is purged.
[0018]
When the fuel carburetor 5 is filled with water vapor, the liquid fuel is sprayed from the fuel tank 6 through the fuel pump 7 into the fuel carburetor 5 through the fuel nozzle 5c, and reaches the high temperature inside the fuel carburetor 5. Evaporate on contact.
[0019]
At this time, since the vapor phase portion in the fuel vaporizer 5 is a mixture of water vapor and fuel vapor, the partial pressure of the fuel vapor is lower than the atmospheric pressure, and the temperature required for vaporizing the liquid fuel is the fuel. The temperature can be lowered as compared to when vaporizing alone.
[0020]
The vaporized liquid fuel is mixed with water vapor from the water vapor outlet 5b and discharged from the gas mixture outlet 5d, sent to the reformer 9, and subjected to water vapor reforming, and the reformed gas is used as fuel for a fuel cell or the like. The
[0021]
If the vaporization temperature of kerosene alone was 300 ° C. or higher, the vaporization temperature was 174 ° C. when S / C = 3 water vapor was used, and vaporization was conducted at a temperature 126 ° C. lower than when no water vapor was mixed. It can be made to.
[0022]
Therefore, by setting the set temperature of the fuel vaporizer low, the thermal decomposition of the liquid fuel due to the high temperature can be prevented, and the liquid fuel can be completely vaporized even at a low temperature, and the liquid fuel is vaporized very well. Things that can be done.
[0023]
In the embodiment described above, an electric heater is used as the vaporization heater 5a. However, by providing the fuel vaporizer 5 with heat exchange fins 5e and exchanging heat with the high-temperature exhaust gas from the reformer 9. If the fuel vaporizer 5 is used as a heat source, the electric heater can be turned off, and energy efficiency can be improved.
[0024]
Alternatively, if the electric heater is used as a heat source during startup and the exhaust heat from the reformer 9 is used during operation, the operation can be smoothly and efficiently performed from startup to operation.
[0025]
In this embodiment, the steam reforming method is used as the reforming method of the reformer 9. However, the present invention is not limited to this, and petroleum liquid fuel or other water-insoluble liquid fuel is mixed with steam or the like. Thus, it is sufficient if a hydrogen-rich gas can be produced by reacting with or without a catalyst. For example, a partial oxidation reforming method or an autothermal reforming method may be used.
[0026]
【The invention's effect】
As described above, the present invention includes a water vaporizer that vaporizes water alone to form water vapor, and a fuel vaporizer that has a heat source and heats and vaporizes liquid fuel, and the water vapor vaporized by the water vaporizer Is supplied to the fuel vaporizer, and when the fuel vaporizer is filled with water vapor, the liquid fuel is supplied to the fuel vaporizer to lower the vaporization temperature of the liquid fuel. Therefore, even if the quality of the liquid fuel varies, it can be surely vaporized.
[Brief description of the drawings]
FIG. 1 is a block diagram of a main part of a fuel cell system to which a vaporizing method according to an embodiment of the present invention is attached.
FIG. 2 is a cross-sectional view of the fuel carburetor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water vaporizer 2 Water tank 3 Water pump 4 Water vapor supply path 5 Fuel vaporizer 5a Vaporization heater 5b Water vapor outlet 5c Liquid fuel spray nozzle 5d Mixer outlet 6 Fuel tank 7 Fuel pump 9 Reformer

Claims (1)

In a method for vaporizing petroleum-based liquid fuel such as kerosene or other water-insoluble liquid fuel, a water vaporizer that vaporizes water alone to form water vapor, and a fuel vaporizer that has a heat source and heats and vaporizes the liquid fuel, The vaporization temperature of the liquid fuel is supplied by supplying the liquid vapor to the fuel vaporizer when the vaporization vaporized by the water vaporizer is supplied to the fuel vaporizer and the fuel vaporizer is filled with the vapor. A method for vaporizing a water-insoluble liquid fuel used in a fuel cell system characterized by being vaporized after being lowered.

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