JP3554921B2 - Fuel evaporator - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel evaporator for liquid raw fuel in a fuel cell system, and more particularly to a fuel evaporator provided with a catalytic combustor.
[0002]
[Prior art]
A fuel cell system (FCS) supplies hydrogen as a fuel gas to a hydrogen electrode (cathode) of the fuel cell and supplies an oxidizing gas containing oxygen to an oxygen electrode (anode) of the fuel cell to generate power. Is the core of the power generation system. This fuel cell system directly converts chemical energy into electric energy, and has recently been receiving attention because of its high power generation efficiency and extremely low emission of harmful substances.
[0003]
In such a system, a liquid raw fuel generally comprising a mixture of methanol and water is injected into a fuel evaporator through a raw fuel injection device, and the raw liquid fuel is evaporated to obtain a raw fuel gas. The raw fuel gas is reformed by a reformer and carbon monoxide is removed to obtain a hydrogen-rich fuel gas, and the fuel gas is supplied to a fuel cell to generate power.
When such a fuel cell system is used under extremely large load fluctuation conditions, for example, when mounted on a fuel cell electric vehicle, the liquid raw fuel is rapidly vaporized in response to a request for an increase in output. When the fuel is injected into the container, the amount of heat of the liquid raw fuel is insufficient to evaporate all of the liquid raw fuel, and a liquid pool of the liquid raw fuel (hereinafter referred to as “liquid pool”) may be generated in the fuel evaporator. In addition, even when the fuel evaporator is not sufficiently heated, such as when starting up the fuel cell system, liquid accumulation is likely to occur.
[0004]
When a liquid pool is generated in the fuel evaporator, the liquid pool evaporates even after the injection of the liquid raw fuel is stopped, so that the raw fuel gas is generated, which deteriorates the responsiveness of the fuel evaporator. Absent. In addition, when the liquid raw fuel is a mixture, the generated liquid pool evaporates first from the easily vaporized components, so that the composition of the raw fuel gas varies, and when the reformer does not exhibit sufficient performance, In some cases, carbon monoxide cannot be sufficiently removed, and the performance of the fuel cell deteriorates.
[0005]
Therefore, in order to effectively prevent the occurrence of liquid pool and improve the responsiveness of the fuel evaporator, and to quickly warm up the fuel evaporator, Japanese Patent Application No. 11-125666 (not disclosed). 9) proposes a fuel evaporator 100 as shown in FIG. The fuel evaporator 100 includes an evaporator main body 110, a superheater 130 at a stage subsequent to the evaporator main body 110, and a raw fuel gas injection device 140 above the evaporator main body 110.
The fuel gas evaporator 100 is supplied with a combustion gas HG obtained by catalytically burning off-gas (gas containing hydrogen) generated in a fuel cell (not shown) by a catalytic combustor (not shown) as a heat source (heat medium gas). . The combustion gas HG reaches the outlet portion 112out from the inlet portion 112in through the inside of the U-shaped heat transfer tubes 112 provided in the evaporation chamber 111 in the evaporator main body 110. Next, the combustion gas HG passes through a combustion gas passage 113 provided at a lower portion of the evaporation chamber main body 110, and is guided to a superheater 130 mounted on the downstream side of the evaporator main body 110. The liquid raw fuel FL composed of a mixture of methanol and water is injected in a mist form from the fuel injection device 140, heated by the heating medium tube 112 and evaporated to become a raw fuel gas FG. The evaporated fuel gas FG may be directly introduced into a subsequent reformer. Further, for the purpose of adjusting the temperature of the raw fuel gas FG, the raw fuel gas FG is superheated through the inside of the steam tube 131 of the superheater 130 and is guided to a reformer (not shown) downstream of the superheater 130.
[0006]
In the fuel evaporator 100, the bottom surface 111b of the evaporation chamber 111 in the evaporator body 110 also serves as the upper surface 113t of the combustion gas passage 113. Therefore, since heat is also supplied from the bottom surface 111b of the evaporation chamber 111, the occurrence of a liquid pool is prevented, and when a liquid pool occurs, the liquid is quickly evaporated. Therefore, the responsiveness of the fuel evaporator 100 is improved.
[0007]
[Problems to be solved by the invention]
However, in the conventional fuel evaporator, since the amount of heat given to the bottom surface 111b is not so large, the effect of preventing the liquid pool from being generated in the evaporation chamber 103 of the fuel evaporator 100 is not sufficient, and the generated liquid pool is efficiently heated.・ Can not be evaporated. Further, there is a demand to effectively use heat from the catalytic combustor.
Further, the configuration of the entire fuel cell system is complicated, and it has been desired to design the entire system more compactly.
Therefore, an object of the present invention is to make it possible to more efficiently heat and evaporate a liquid pool in an evaporator with a relatively simple configuration, and to design a compact fuel cell system as a whole, and An object of the present invention is to provide a fuel evaporator capable of effectively utilizing heat from a catalytic combustor.
[0008]
[Means for Solving the Problems]
Ie, the present invention includes an evaporation chamber for evaporating the liquid raw fuel that is injected from the fuel injection device high temperature heating medium,
A fuel evaporator comprising a catalyst combustor provided adjacent to the evaporation chamber,
The evaporation chamber has a heating medium tube through which the high-temperature heating medium supplied from the catalytic combustor passes,
The catalyst combustor is arranged on an upstream side in a direction in which the high-temperature heat medium passes .
With this configuration, compared to the case where a separate combustor is provided as in the conventional fuel evaporator, the liquid raw fuel adhered as droplets to the wall surface of the evaporation chamber or the liquid raw fuel existing as a liquid pool is provided. Thus, more heat can be applied more quickly. Further, since the catalytic combustor is provided adjacent to the fuel cell, the whole system can be designed to be more compact.
[0009]
Further, in the fuel evaporator of the present invention, the heat medium tube is a heat medium tube that allows the high temperature heat medium to pass from the high temperature side to the low temperature side of the evaporation chamber, and the catalytic combustor has a high temperature medium of the heat medium tube. Preferably, it is adjacent or closely attached to the side .
With such a configuration, it is possible to more quickly apply more heat to the liquid raw fuel or the liquid pool of the liquid raw fuel that has adhered as droplets in a portion that is in close contact with the catalytic combustor.
In the above aspect, the catalytic combustor is in close contact with the evaporation chamber, and a contact surface between the catalytic combustor and the evaporation chamber forms a high-temperature side wall surface of the evaporation chamber , and the high-temperature side wall surface is preferably comprises a shape along the outer shape of the heating medium tube which is near placed on the most the hot side wall surface of the provided evaporation chamber heating medium tube through which the high temperature thermal medium.
With this configuration, it is possible to reduce the liquid pool space below the evaporation chamber.
[0010]
In the fuel evaporator of the present invention, the upper part of the catalytic combustor may be formed thicker than other peripheral parts. With this configuration, a heat mass is provided above.
Conversely, in the fuel evaporator of the present invention, the lower part of the catalytic combustor can be formed thicker than other peripheral parts. With this configuration, a heat mass is provided below.
[0011]
In the fuel evaporator of the present invention, the contact surface in which the catalytic combustor is in close contact with the evaporation chamber forms a bottom surface of the evaporation chamber, and the bottom surface is provided in the evaporation chamber and a heat medium tube through which the high-temperature medium passes. among the most the has a close placement to shape along the outer shape of the heating medium tubes to the bottom aspect, configured to have the catalytic combustor of the bottom surface recessed toward the central portion from the peripheral portion shape May be. With this configuration, the calorific value near the center of the catalytic combustor becomes higher than that near the outer periphery, and more stored liquid can be evaporated.
Further, in the fuel evaporator of the present invention, a high-temperature heat medium generating means provided adjacent or in close contact with at least one peripheral surface of the evaporation chamber may be formed so as to be separable from the evaporation chamber.
With this configuration, the catalyst combustor can be detached and attached at the time of inspection and replacement of the catalyst combustor.
[0012]
Further, in the fuel evaporator of the present invention, the catalytic combustor can be formed in a substantially rectangular shape that is long in the length direction. With this configuration, the upper surface in close contact with the evaporation chamber is formed wider than when the catalytic combustor is formed in a substantially circular shape.
Further, in the fuel evaporator of the present invention, the catalytic combustor may be formed so that its cross section is substantially circular with a lower chord.
With this configuration, the area capable of transferring heat is increased, so that heat can be efficiently transmitted to the evaporation chamber, and in addition, the surface area other than the upper surface is reduced, so that heat escape is reduced. ]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described more specifically with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.
(Explanation of the whole fuel cell system)
FIG. 1 is an overall system diagram of a fuel cell system according to the present invention. As shown in FIG. 1, the fuel cell system comprises a fuel evaporator 1 for evaporating a liquid raw fuel, and a raw fuel gas obtained by evaporating the liquid raw fuel in the fuel evaporator 1 to react on a solid catalyst. A reformer 2 for converting the fuel gas, a CO remover 3 for removing carbon monoxide in the fuel gas generated by the reformer 2, and hydrogen in the fuel gas supplied from the CO remover 3. A fuel cell 5 that generates electricity by reacting with oxygen in the air compressed by an air compressor 4 that is an oxidant supply unit, and a gas-liquid separator that separates and removes moisture from off-gas of a hydrogen electrode of the fuel cell 5 6 and a combustion burner 7 having a supply line for an auxiliary fuel (for example, methanol) for burning off-gas supplied from the gas-liquid separation device 6 to generate a gas serving as a heating source of the fuel evaporator 1. You.
[0014]
When obtaining a raw fuel gas, a predetermined amount of a liquid raw fuel (for example, a mixed fuel of methanol and water) is supplied from a liquid raw fuel storage tank T to the fuel evaporator 1 by a pump. The liquid raw fuel supplied to the evaporation chamber 11 of the fuel evaporator 1 is injected by the raw fuel injection device 40 and evaporated as raw fuel gas. As a heating source for the evaporating chamber 11, a high-temperature gas generated by catalytically combusting off-gas of the hydrogen electrode of the fuel cell in the catalytic combustor 20 during operation is used. The auxiliary burner (for example, methanol) can be burned by the combustion burner 7 to secure a necessary amount of heat.
[0015]
The raw fuel gas generated in the evaporation chamber 11 is introduced into the reformer 2 and reacted on a solid catalyst (for example, a Cu—Zn-based catalyst) to produce a hydrogen-rich fuel gas. Further, in the hydrogen-rich fuel gas generated in the reformer 2, the carbon monoxide in the gas is removed by the CO remover 3, and the hydrogen-rich fuel gas is oxidized with hydrogen in the fuel gas supplied from the CO remover 3. It is introduced into a fuel cell 5 that generates electricity by reacting with oxygen in the air compressed by an air compressor 4 that is an agent supply unit. The hydrogen gas off-gas after the reaction in the fuel cell 5 is separated and removed in the gas-liquid separator 6 and then burned in the catalytic combustor 20 to serve as a heating source for the evaporation chamber 11.
[0016]
The present invention relates to the fuel evaporator 1 in such a fuel cell system, wherein the catalytic combustor 20 is provided adjacent to a specific position. Hereinafter, the fuel evaporator 1 of the present invention will be described with reference to FIGS.
FIG. 2 is a partially cutaway plan view of the fuel evaporator of the present embodiment, FIG. 3 is a sectional view taken along line AA ′ of FIG. 2, and FIG. 4 is a sectional view taken along line BB ′ of FIG. FIG. 5 is a diagram, and FIG. 5 is BB ′ of FIG. 2 and shows another embodiment of the present invention.
The fuel evaporator 1 includes an evaporator main body 10 including an evaporating chamber 11, a catalytic combustor 20 provided adjacent to, particularly in close contact with, the evaporating chamber 11, and a high-temperature heat medium provided around the evaporating chamber 11. The fuel gas is mainly constituted by a combustion gas passage 12 which is a passage, and the raw fuel gas evaporated in the evaporating chamber 11 is superheated by the combustion gas passing through the combustion gas passage in the superheating section 30.
(Evaporation chamber)
The evaporation chamber 11 is provided in the upper part of a room surrounding the U-shaped heat medium tubes 12, a tube holding plate 12a that holds both ends of the heat medium tubes 12, and a plurality of U-shaped heat medium tubes 12 arranged in parallel. It is mainly constituted by a raw fuel injection device 40 configured to inject liquid raw fuel to the outside of the heat medium tube 12 in the direction of the inlet side of the heat medium tube 12.
The heat medium tube 12 transfers the combustion gas HG, which is a high-temperature heat medium capable of evaporating the liquid raw fuel generated in the catalytic combustor 20, from the bottom 12in (below the heat medium tube) to the upper 12out (above the heat medium tube). And a tube for flowing the fuel gas flow path 13 to the fuel gas flow path 13. The tube is made of a metal such as SUS316 having excellent heat resistance and corrosion resistance, such as stainless steel.
[0017]
The raw fuel injection device 40 is a one-fluid nozzle injection device, for example, an injector, and is for injecting (spraying) the liquid raw fuel FL into fine droplets. The injection direction is the direction along the heat medium tube 12 (the direction toward the heat medium tube holding plate 12a) so as to be attached to the upper part of the evaporation chamber 11 and to effectively use the retained heat of the high-temperature combustion gas HG. The injection amount is controlled by the back pressure of the nozzle (the injection amount is proportional to the square root of the back pressure).
Around the evaporating chamber 11, there is provided a combustion gas passage 13 which serves both to keep the temperature of the evaporating chamber 11 and to heat the evaporating chamber 11 and to flow the combustion gas discharged from the evaporating chamber 11. Then, the combustion gas that has passed through the combustion gas passage 13 is passed to the body side, and the raw fuel gas evaporated in the evaporation chamber 11 is caused to flow to the pipe side, so that the raw fuel gas is saturated so that the raw fuel gas is not condensed. It is connected to a superheater 30 which is a shell-and-tube heat exchanger for heating to a temperature higher than the temperature.
[0018]
(Catalyst combustor)
The catalytic combustor 20 is a combustor that generates high-temperature combustion gas HG by catalytically burning the off-gas OG, and is mainly configured by an inlet passage 21, a catalyst layer 22, and an outlet passage 23 of the off-gas OG. The surroundings are covered with a top plate 20t, a bottom plate 20b, and side plates 20s and 20s' made of a metal such as stainless steel having excellent heat resistance and corrosion resistance such as SUS316 like the heat medium tube (described later). 6 to 8). In a preferred embodiment of the present invention, the upper plate 20t also serves as the bottom of the evaporator 11. That is, it is preferable that the upper surface of the catalytic combustor 20 is directly attached to the lower surface of the evaporator 11.
The cross-sectional shape of the catalyst layer 22 is preferably a substantially rectangular shape having a width corresponding to the width of the lower surface 11b of the evaporation chamber 11 in order to increase a heat transfer area with the evaporation chamber 11, and includes a honeycomb shape. The catalyst is filled. As the material of the catalyst, a Pt-based catalyst is used. As carriers, silica-based and alumina-based carriers are often used. Before and after the catalyst layer 22, an inlet flow path 21 for introducing an object to be burned into the catalytic combustor 20, and when the high-temperature combustion gas generated in the catalyst layer 22 flows downstream, the gas flows in a direction 180 °. An outlet flow path 23 (in the example of the figure, the cross section is a semicircle) formed of a partition plate 24 that divides the inside of the combustion gas passage 13 so as to be changed, An off-gas OG of the hydrogen electrode, that is, a mixed gas of hydrogen and oxygen is introduced from the inlet channel 21 and catalytically combusted in the catalyst layer 22 to produce a high-temperature combustion gas HG (typically 650 to 700 ° C.). The heated combustion gas HG is guided from the outlet channel 23 to the evaporation chamber 11.
[0019]
In the present invention, it is essential that the catalytic combustor 20 is provided adjacent to the evaporation chamber 11, and in FIGS. 2 to 4, the top plate 20 t of the catalytic combustor is particularly closely attached below the evaporation chamber 11. Although shown, the side surface 20 s or 20 s ′ of the catalytic combustor 20 may be configured adjacent to the side surface of the evaporation chamber 11.
With this configuration, the heat of the catalytic combustor 20, which has been heated to a high temperature by catalytic combustion, is transmitted to the radiation or the portion of the evaporation chamber 11 adjacent to the catalytic combustor 20. In addition, as compared with the case where the catalyst combustor 20 is provided separately from the conventional catalyst combustor 20, it is not necessary to connect the catalyst combustor 20 and the evaporator main body 10 with piping, so that not only the configuration is simplified, but also a more compact design can be achieved. Become.
In addition, as shown in FIG. 5, a thin heater H or the like may be retrofitted between the catalytic combustor 20 and the evaporation chamber 11.
In this case, even when the catalytic combustor 20 does not rise, it is possible to apply heat from the heater H to the evaporation chamber 11 to promote evaporation.
Therefore, the term “adjacent” as used in the present invention means that the catalytic combustor 20 is arranged at a position where heat from the catalytic combustor 20 is effectively transferred to the evaporation chamber 11.
By the heat transmitted to the evaporator body 10 in this manner, the liquid raw fuel FL and the liquid pool existing as droplets on the wall surface of the evaporating chamber 11 evaporate quickly to become the raw material gas FG.
[0020]
In this case, the position where the catalytic combustor 20 is provided is particularly limited as long as it is possible to transmit heat to the evaporation chamber 11 and evaporate the liquid raw fuel existing as a liquid in the evaporator 11 as described above. Although not intended, it is preferable that the upper surface 20t of the catalytic combustor 20 and the lower surface of the evaporating chamber 11 be in close contact with each other, as shown in FIGS. Further, in order to transmit more heat to the evaporation chamber 11, it is preferable that the cross-sectional shape of the catalytic combustor 20 be a substantially rectangular shape having a width corresponding to the width of the lower surface 11 b of the evaporation chamber 11 and extending in the length direction.
With this configuration, heat can be efficiently transmitted to the entire evaporating chamber 11, particularly to the lower surface 11 b where the liquid pool is likely to occur.
[0021]
Hereinafter, a preferred embodiment of the present invention in which the upper surface 20t of the catalytic combustor 20 is attached to the lower surface 11b of the evaporator 11 will be described with reference to FIGS. In these figures, the upper surface 20t of the catalytic combustor 20 is shown as also serving as the lower surface 11b of the evaporator 11, but the upper surface 20t of the catalytic combustor 20 and the lower surface 11b of the evaporator 11 are provided separately. This is also a part of the present invention.
6 to 8 are schematic sectional views taken along the lines B and B ′ of FIG. 2 showing the embodiment of the present invention, and schematically show the close contact relationship between the catalytic combustor of the present invention and the evaporation chamber.
As shown in FIG. 6A, a heating medium tube 12 having a substantially circular cross section is laid on the lower surface 11b of the evaporation chamber 11. Among the heating medium tube 12, the most upper plate 20t of the catalytic combustor 20 as the catalytic combustor 20 to close along the cross-sectional shape of the placed has been lowermost surface 12in is a wave-like shape. With this configuration, as shown in FIG. 6B, the liquid pool space R where the liquid pool below the evaporation chamber 11 is more likely to be generated as compared with the case where the upper surface 20t of the catalytic combustor 20 is formed flat. It can be reduced.
[0022]
Further, as shown in FIG. 7A, when the upper surface 20t of the catalytic combustor 20 is formed thicker than the other peripheral portions 20b, 20s, and 20s', heat is generated above the thick catalytic combustor 20. Since the mass is provided, the transient response response is improved, and the stored liquid fuel can be evaporated even after catalytic combustion.
Conversely, as shown in FIG. 7B, the lower surface 20b of the catalytic combustor 20 can be formed thicker than the other peripheral portions 20t and 20s'. With this configuration, the heat mass is stored below the catalytic combustor 20, the efficiency of heat transfer with the evaporating chamber 11 is improved, and the radiating area is enlarged. The combustor 20 functions to warm and start the fuel evaporator 1 and obtain the raw fuel gas FG.
[0023]
Further, as shown in FIG. 8, the upper surface 20t of the catalytic combustor 20 may be formed to have a shape depressed from the peripheral edge toward the center, and in particular, the cross section of the catalytic combustor 20 is formed in a substantially semicircular shape of the lower chord. Is preferred. By arranging the lowermost part of the evaporating chamber 11 where the liquid pool is most likely to exist near the center of the catalytic combustor 20 having the largest amount of heat, the amount of heat near the center of the catalytic combustor 20 is higher than that near the outer periphery. , So that more liquid pools can be evaporated, and the amount of heat is used without waste and evaporation is performed quickly. Further, when the cross section of the catalytic combustor 20 is formed in a substantially semicircular shape with a lower chord, the surface area other than the upper surface plate 20t can be reduced, so that the effect of reducing heat loss can be obtained.
[0024]
Further, in the fuel evaporator 1 of the present invention, the catalytic combustor 20 provided adjacent to or in close contact with the evaporating chamber 11 can be provided detachably. At this time, the entire catalytic combustor 20 can be detachably provided. However, it is general that the catalyst layer 22 is detachably provided. With this configuration, when the catalytic combustor 20 is inspected or replaced, the catalytic combustor, in particular, the catalyst layer 22 that needs to be inspected or replaced can be detached, so that the inspection can be easily performed and the cost as a replacement part can be reduced. It becomes possible. In addition, a thin member having high thermal conductivity may be sandwiched between the catalytic combustor 20 and the evaporation chamber 11. In this case, distortion due to thermal stress caused by the temperature difference between the catalytic combustor 20 and the evaporation chamber 11 is avoided, and the strength against vibration input is improved.
[0025]
【The invention's effect】
As described above, the fuel evaporator of the present invention in which the catalytic combustor is provided adjacent to the evaporating chamber is provided on the wall surface of the evaporating chamber in comparison with the case where a separate combustor is provided as in the conventional fuel evaporator. It is possible to more quickly apply more heat to the liquid raw fuel and the liquid pool in the evaporation chamber attached as liquid droplets, and it is possible to easily evaporate these liquid droplets and liquid pool. In addition, there is no need to connect the catalytic combustor and the evaporator body with a pipe, so that a more compact design can be achieved.
Further, when the catalytic combustor is provided in close contact with the evaporation chamber, the heat transfer effect increases.
Further, the contact surface of the catalytic combustor in close contact with the evaporation chamber, to form a bottom surface of the evaporation chamber, the bottom surface is closer placed on the bottom of most evaporator of the heat medium tubes through which hot medium provided in the evaporation chamber When the shape is provided along the outer shape of the heat medium tube, the liquid pool space below the evaporation chamber can be reduced, thereby reducing the amount of the liquid pool and enabling rapid liquid evaporation.
Also, if the upper part of the catalytic combustor is formed thicker than the other peripheral parts, a heat mass is provided above, so that the liquid pool can be evaporated even after catalytic combustion, and the utilization rate can be increased. Become. Conversely, if the lower part of the catalytic combustor is formed thicker than the other surrounding parts, a thermal mass is provided below, so that the catalyst evaporator functions quickly even in the case of a sudden request for raw fuel to evaporate and warms the evaporator. Can be raised.
Furthermore, if the upper surface of the catalytic combustor is configured to be concave from the periphery to the center, the amount of heat near the center of the catalytic combustor will be higher than that near the outer periphery, allowing more liquid pools to evaporate Thus, the amount of heat is used without waste, and evaporation is quickly performed.
Further, if the catalytic combustor provided adjacent to or in close contact with the evaporation chamber is formed so as to be separable from the evaporation chamber, the inspection and replacement of the catalytic combustor can be performed by detaching the catalytic combustor, which facilitates inspection. The cost as a replacement part can be reduced.
In addition, when the catalyst combustor is formed in a substantially rectangular shape that is long in the length direction, the upper surface adjacent to or in close contact with the fuel evaporator is formed wider than when the catalyst combustor is formed in a substantially circular shape. The area that can be transmitted increases. Therefore, heat can be efficiently transmitted to the evaporation chamber.
Further, when the cross section of the catalytic combustor is formed so as to have a substantially circular shape with a lower chord, the area capable of transmitting heat increases, and in addition to efficiently transmitting heat to the evaporation chamber, the surface area other than the upper surface is increased. , Heat escape is reduced, and heat can be more efficiently transferred to the evaporation chamber.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a fuel cell system in which a fuel evaporator of the present embodiment is used.
FIG. 2 is a partially cutaway plan view of the fuel evaporator of the embodiment.
FIG. 3 is a sectional view taken along line AA ′ of FIG. 2;
FIG. 4 is a sectional view taken along line BB ′ of FIG. 2;
FIG. 5 is BB ′ of FIG. 2 and shows another embodiment of the present invention.
6 (a) and 6 (b) are cross-sectional views taken along the line BB 'of FIG. 2 showing another embodiment of the present invention.
FIGS. 7A and 7B are cross-sectional views of another embodiment of the present invention, taken along line BB ′ of FIG. 2;
FIG. 8 is a sectional view taken along the line BB ′ of FIG. 2, showing still another embodiment of the present invention.
FIG. 9 is a sectional view showing a conventional fuel evaporator.
[Explanation of symbols]
FG Raw fuel gas FL Liquid raw fuel OG Off gas HG Combustion gas H Heater 1 Fuel evaporator 2 Reformer 3 CO remover 10 Evaporator body 11 Evaporation chamber 12 Heat medium tube 12a Heat medium tube lower 12b Heat medium tube upper 13 Combustion Gas passage 20 Catalytic combustor 20t Catalytic combustor upper surface 20b Catalytic combustor lower surface 20s, 20S 'Catalytic combustor side surface 21 Inlet passage 22 Catalyst layer 23 Outlet passage 30 Superheater 40 Raw fuel injection device

Claims (4)

An evaporation chamber for evaporating liquid raw fuel injected from the raw fuel injection device by a high-temperature heat medium,
A fuel evaporator comprising a catalytic combustor provided adjacent to the evaporation chamber,
The evaporation chamber has a heating medium tube through which the high-temperature heating medium supplied from the catalytic combustor passes,
The fuel evaporator is characterized in that the catalytic combustor is arranged on an upstream side in a direction in which the high-temperature heat medium passes . The heat medium tube is a heat medium tube that allows the high-temperature heat medium to pass from the high temperature side to the low temperature side of the evaporation chamber, and the catalytic combustor is adjacent to or close to the high temperature side of the heat medium tube . The fuel evaporator according to claim 1, wherein: The catalytic combustor is in close contact with the evaporating chamber, and a contact surface between the catalytic combustor and the evaporating chamber forms a high-temperature side wall surface of the evaporating chamber, and the high-temperature side wall surface is provided in the evaporating chamber. the fuel according to claim 1 or 2, characterized in that it comprises a shape most along the contour of the hot side near placed has been the heating medium tube wall of the high temperature thermal medium heat medium tubes through is Evaporator. Wherein the hot side wall surface of the evaporator, a fuel vaporizer according to claim 3, characterized in that it has a recessed from the periphery toward the center portion.

Images