JP4556316B2 - Control of raw material input to reformer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control technique at the start-up of a fuel reformer for generating hydrogen-rich fuel gas from a raw fuel containing a hydrocarbon-based compound.
[0002]
[Prior art]
In the reformer, a hydrogen-rich fuel gas is generated from a raw fuel containing a hydrocarbon compound by utilizing a steam reforming reaction. The supply amount of raw fuel and the supply amount of water to the reformer are controlled to appropriate values in consideration of various chemical reactions in the reformer.
[0003]
As a technique for controlling the amount of raw fuel and water supplied to the reformer, for example, a technique described in Japanese Patent Application Laid-Open No. 11-307110 is known. In this method, the molar ratio (S / C) between the water vapor supplied to the reformer and the carbon in the raw fuel is adjusted in accordance with fluctuations in the load of the fuel cell. As a result, it is possible to obtain an appropriate amount of hydrogen gas corresponding to the load variation of the fuel cell.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional technology, problems at the time of starting the reformer are not considered. That is, at the time of starting the reformer, the temperature of the reforming catalyst is not sufficiently high, so that the reforming reaction is not sufficiently activated. As a result, there is a problem in that even when a large amount of raw fuel is supplied at startup, most of the fuel is discharged from the reformer without being reacted.
[0005]
In particular, the boiling point of methanol is about 65 ° C., and the boiling point is much lower than that of water. Therefore, a methanol-rich raw material gas is supplied to the reforming catalyst when the methanol reformer is started. Therefore, in the methanol reformer, the problem that a large amount of unreacted methanol is discharged at the time of startup is remarkable. However, such a problem is not limited to methanol, but is a problem common to reformers for raw fuels containing hydrocarbon compounds having a boiling point lower than that of water.
[0006]
The present invention has been made to solve the above-described conventional problems, and provides a technique capable of reducing the amount of unreacted raw fuel discharged from the reformer when the reformer is started. The purpose is to do.
[0007]
[Means for solving the problems and their functions and effects]
In order to achieve the above object, the fuel reformer of the present invention comprises: A vaporization unit that vaporizes both the raw fuel and water used for a steam reforming reaction of the raw fuel, a steam reforming unit that reforms the raw fuel using a steam reforming reaction, and the steam reforming A selective oxidation unit that oxidizes carbon monoxide contained in the reformed gas reformed in the mass part using a selective oxidation reaction is arranged in this order. A reformer and the raw fuel The vaporizer The raw fuel supply unit for supplying to the front Water Water used for steam reforming reaction The vaporizer A water supply unit for supplying the raw fuel, a mole number C of carbon contained in the raw fuel supplied from the raw fuel supply unit in at least a part of the period when the reformer is started, and the water supply Value of the ratio (C / S) with the number of moles S of water supplied from the section The Less than a predetermined appropriate value during steady operation of the reformer By reducing the unreacted raw fuel discharged after passing through the vaporization unit, the steam reforming unit, and the selective oxidation unit, And a control unit that controls the raw fuel supply unit and the water supply unit.
[0008]
According to this configuration, since the ratio of the raw fuel is reduced when the reformer is started, the amount of unreacted raw fuel discharged can be reduced.
[0009]
The control unit determines that the value of the ratio (C / S) is at the start of the reformer. Continuously The raw fuel supply unit and the water supply unit may be controlled to increase.
[0010]
According to this configuration, the proportion of raw fuel gradually increases. Continuously Therefore, the amount of raw fuel corresponding to the increased activation of the reforming reaction can be supplied to the reformer, and the amount of unreacted raw fuel discharged can be reduced.
[0011]
The raw fuel preferably contains a hydrocarbon compound having a boiling point lower than that of water as a main component. For example, methanol can be used as the raw fuel.
[0012]
Since the problem of emission of unreacted raw fuel at start-up is more serious with respect to hydrocarbon compounds having a boiling point lower than that of water, the main component is a hydrocarbon compound having a boiling point lower than that of water, such as methanol. The effect of the present invention is particularly remarkable when fuel is used.
[0013]
The present invention can be realized in various modes, for example, a fuel reformer and a control method thereof, a fuel cell system and a control method thereof, and a computer for realizing the functions of these methods or devices. The present invention can be realized in the form of a program, a recording medium recording the computer program, a data signal including the computer program and embodied in a carrier wave, and the like.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
B. Other examples:
C. Variations:
[0015]
A. First embodiment:
FIG. 1 is an explanatory diagram showing the configuration of a fuel cell system as a first embodiment of the present invention. The fuel cell system 200 includes a raw fuel tank 10 that stores methanol, a water tank 20 that stores water, and a reformer that generates fuel gas (also referred to as “reformed gas”) from raw fuel by a reforming reaction. 30, a fuel cell 40, and a controller 50. The reformer 30 includes a vaporization section 32 that vaporizes the reforming raw material, a heating section 34 that supplies heat to the vaporization section 32, a reforming section 36 that contains a reforming catalyst, and carbon monoxide in the reformed gas. And a selective oxidation unit 38 that performs selective oxidation for reducing the amount of oxidation.
The vaporization unit 32 and the heating unit 34 may be collectively referred to as an “evaporation unit”.
[0016]
A raw fuel supply path 102 is connected to the raw fuel tank 10, and a water supply path 108 is connected to the water tank 20. The raw fuel supply passage 102 is branched into two branch passages 104 and 106. The first branch flow path 104 merges with the water supply path 108, and the flow path 110 after the merge is connected to the vaporization unit 32. On the other hand, the second branch channel 106 is connected to the heating unit 34. The first branch flow path 104 is provided with a flow meter 51 and a pump 52, and the second branch flow path 106 is also provided with a flow meter 53 and a pump 54. The water supply path 108 is also provided with a flow meter 55 and a pump 56.
[0017]
The raw fuel tank 10, the raw fuel supply path 102 and its first branch flow path 104, the flow meter 51, and the pump 52 constitute a raw fuel supply section in the present invention. Moreover, the water tank 20, the water supply path 108, the flow meter 55, and the pump 56 constitute a water supply unit in the present invention.
[0018]
Methanol and water are sucked out by the pumps 52 and 56, respectively, and introduced into the vaporizing section 32 in a mixed state. This mixture is hereinafter referred to as “reforming raw material”. The reforming raw material is vaporized in the vaporization unit 32 to become steam (methanol vapor and water vapor), and is supplied to the reforming unit 36. This gaseous reforming material (referred to as “reforming material gas”) is converted into a hydrogen gas-rich fuel gas HRG by a chemical reaction in the reforming unit 36 and the selective oxidation unit 38. The chemical reaction in the reforming unit 36 will be described later.
[0019]
The fuel gas HRG generated by the reformer 30 is introduced into the fuel gas passage 42 in the fuel cell 40 via the fuel gas passage 112. Air AR 40 is supplied to the air passage 44 in the fuel cell 40 by an air pump 46. As the air pump 46, for example, a blower can be used. In the fuel cell 40, power is generated by an electrochemical reaction between hydrogen in the fuel gas HRG and oxygen in the air AR40, and as a result, hydrogen in the fuel gas HRG is consumed.
[0020]
The exhaust path 114 of the fuel exhaust gas from the fuel cell 40 is returned to the heating unit 34 of the reformer 30. The heating unit 34 burns hydrogen in the fuel exhaust gas and supplies the heat to the vaporization unit 32. As the heating unit 34, a device that promotes a combustion reaction of fuel exhaust gas or methanol using a noble metal catalyst such as a platinum catalyst or a palladium catalyst, or a device that burns fuel exhaust gas or methanol using a burner may be used. it can. In the vaporization unit 32, the reforming raw material is vaporized by the heat given from the heating unit 34. When the heat generated by the combustion of the fuel exhaust gas is insufficient, methanol, which is the raw fuel, is supplied to the heating unit 34 via the pump 54. Further, the heating air AR 34 is supplied to the heating unit 34 by the first air supply unit 64.
The air supply unit 64 includes an air pump 64a, a pressure gauge 64b, and an electric valve 64c. A second air supply unit 66 similar to this supplies the air AR 36 to the mixing chamber 36 a upstream of the reforming unit 36.
[0021]
The reforming unit 36 is provided with a temperature sensor 92 for measuring the temperature of the reforming catalyst. In addition, an oxygen concentration sensor 94, a carbon monoxide concentration sensor 96, and a raw fuel sensor 98 (in this embodiment, a methanol concentration sensor) are provided in the fuel gas flow path 112 between the reformer 30 and the fuel cell 40. ing. The controller 50 executes control of the fuel cell system 200 using the measured values measured by a plurality of sensors including these sensors 92, 94, 96, 98 and the flow meters 51, 53, 55 as control inputs. . In FIG. 1, for the sake of illustration, the controller 50 shows only connections to some components (sensors and pumps), and illustrations of connections to other components are omitted.
[0022]
The main chemical reaction utilized in each part in the reformer 30 is as follows. In the reforming part 36, the following steam reforming reaction of methanol mainly occurs.
[0023]
CH _Three OH + H ₂ O → CO ₂ + 3H ₂ -49.5 (kJ / mol) (1)
[0024]
As a catalyst for the steam reforming reaction of methanol, for example, a copper-zinc catalyst can be used. When the air AR 36 is supplied to the reforming unit 36 by the second air supply unit 66, the following partial oxidation reaction also occurs in the reforming unit 36.
[0025]
CH _Three OH + (1/2) O ₂ → CO ₂ + 2H ₂ +189 (kJ / mol) (2)
[0026]
The steam reforming reaction of the above formula (1) is an endothermic reaction, and the partial oxidation reaction of the formula (2) is an exothermic reaction. When the reformer 30 is started, the temperature of the reforming catalyst can be raised using heat generated by the partial oxidation reaction. Further, during the steady operation of the reformer 30, it is possible to maintain the reforming section 36 at an appropriate operating temperature by performing both at an appropriate ratio. The air AR 36 supplied to the reforming unit 36 is used for the partial oxidation reaction described above, and is hereinafter referred to as “partial oxidation air”.
[0027]
The steam reforming reaction of the above formula (1) can be considered to be the result of the following two reactions, for example.
[0028]
CH _Three OH → CO + 2H ₂ -90.0 (kJ / mol) (3)
CO + H ₂ O → CO ₂ + H ₂ +40.5 (kJ / mol) (4)
[0029]
However, a part of the carbon monoxide generated by the reaction of the formula (3) is supplied as it is from the reforming unit 36 to the selective oxidation unit 38 without being converted into carbon dioxide. Therefore, in the selective oxidation unit 38, the carbon monoxide concentration is reduced by the following selective oxidation reaction.
[0030]
CO + (1/2) O ₂ → CO ₂ +279.5 (kJ / mol) (5)
[0031]
As a catalyst for the selective oxidation reaction, a precious metal catalyst such as a platinum catalyst or a ruthenium catalyst, an aluminum catalyst, or the like can be used. The gas that has passed through the selective oxidation unit 38 is supplied to the fuel cell 40 as a hydrogen-rich fuel gas HRG. As is well known, the reason for reducing the carbon monoxide concentration in the selective oxidation unit 38 is that the carbon monoxide has a poisoning action on the platinum catalyst in the fuel cell 40, and the electromotive force of the fuel cell 40 is reduced. This is because it lowers.
[0032]
By the way, as understood from the above formula (1), in an ideal steam reforming reaction, 1 mol of water molecules is required for 1 mol of carbon atoms. However, it is known that in the actual reforming reaction, the reforming efficiency (hydrogen molecule generation rate) is higher when a little more water is added. The ratio of the number of moles of water molecules to 1 mole of carbon atoms in the raw material gas supplied to the reforming section 36 is called the steam-carbon ratio (S / C). When the reformer 30 using methanol as a raw fuel is in a steady operation state, an appropriate value of the steam-carbon ratio (S / C) is, for example, about 2.0.
[0033]
FIG. 2 is an explanatory diagram showing a state of control of the amount of reforming material input in the comparative example. FIG. 2A shows the change over time in the amount of water charged when the reformer 30 is started.
Here, “activation of the reformer” means activation from a room temperature state. 2B shows the amount of methanol input, FIG. 2C shows the reciprocal of the steam-carbon ratio (S / C), and FIG. 2D shows the outlet methanol concentration. 2A, 2B, and 2D is a relative value scale, while the vertical axis in FIG. 2C is an absolute value scale. The input amounts of water and methanol are calculated from the flow rates measured by the respective flow meters 55 and 51 (FIG. 1). The reciprocal of the steam carbon ratio (S / C) is calculated from the input amounts of water and methanol. The outlet methanol concentration is measured by the methanol concentration sensor 98.
[0034]
In this comparative example, when the operation of the reformer 30 is started at time t0, only the heating unit 34 is operated and the temperature is increased until time t1. When the temperature of the heating unit 34 increases to some extent, supply of water and methanol to the vaporization unit 32 is started from time t1. The input amount of water and the input amount of methanol are set to substantially constant values LW1 and LM1 from time t1, respectively. The reciprocal of the steam-carbon ratio (S / C) is also a constant value (C / S) after time t1. ₁ (= 0.5). This (C / S) ₁ The value of corresponds to an appropriate value (about 2.0) of the steam carbon ratio (S / C) during steady operation.
[0035]
By the way, since the temperature of the reforming catalyst in the reforming unit 36 is not so high at the time t1, even if a large amount of methanol is added after the time t1, most of the methanol undergoes a chemical reaction in the reforming unit 36. Does not cause. In particular, since methanol has a lower boiling point than water, methanol-rich fuel gas is supplied to the reforming unit 36, and a large amount of unreacted methanol is discharged from the reformer 30 at the time of startup. As a result, as shown in FIG. 2D, a phenomenon occurs in which the outlet methanol concentration rapidly rises from time t1.
[0036]
In addition, since methanol-rich fuel gas is supplied to the reforming unit 36, some unreacted methanol is condensed inside the reforming unit 36 (particularly the rear end side of the reforming catalyst) or inside the selective oxidation unit 38. Then, the phenomenon of storing will also occur. The methanol condensed in this way gradually evaporates when the temperature of the reforming catalyst rises and a sufficient reforming reaction starts to occur, but the outlet methanol concentration slowly decreases until this evaporation is completed. That is, in this comparative example, even after the temperature of the reforming catalyst rises and a sufficient reforming reaction starts to occur, the outlet methanol concentration does not decrease easily, and the fuel cell 40 contains a considerable amount of unreacted methanol. The phenomenon that fuel gas is supplied occurs.
[0037]
FIG. 3 is an explanatory diagram showing the manner of controlling the input amount of the reforming material in the first embodiment of the present invention. As in the case of FIG. 2, the heating unit 34 is heated from time t0 to time t1, and the supply of water and methanol is started from time t1. Also in the first embodiment, the amount of water input is maintained at a substantially constant value LW1 from time t1, but the amount of methanol input is different from the comparative example. That is, the amount of methanol input is substantially zero at time t1, then increases substantially linearly, and reaches a substantially constant value LM1 at time t2.
[0038]
The reciprocal of the steam-carbon ratio (S / C) shown in FIG. 3C changes according to the change in the amount of methanol input. That is, this value (C / S) is substantially zero at time t1, and thereafter increases substantially linearly, and is substantially constant (C / S) at time t2. ₁ To reach. This value (C / S) ₁ Is about 0.5, which corresponds to an appropriate value (about 2.0) of the steam-carbon ratio (S / C) during steady operation.
[0039]
As shown in FIG. 3 (D), in the first embodiment, the outlet methanol concentration increases from time t1, but the peak remains at a lower value compared to the comparative example (FIG. 2 (D)). In addition, it can be understood that the outlet methanol concentration rapidly decreases after reaching the peak. Therefore, it is possible to supply the fuel cell 40 from the reformer 30 with a high-quality fuel gas HRG having a low methanol concentration from a point earlier than the comparative example.
[0040]
The change in the outlet methanol concentration as shown in FIG. 3D is presumed to be caused by the following phenomenon. That is, the temperature of the reforming catalyst is not sufficiently increased immediately after the start of the methanol addition, but since a small amount of methanol is added, a considerable portion of the supplied methanol is partially oxidized (the above formula (2)), etc. This is used for exothermic reaction to raise the temperature of the reforming catalyst. Therefore, even immediately after the start of the addition of methanol, not much unreacted methanol is not discharged. In addition, when the amount of unreacted methanol is small, the amount of methanol condensed in the reformer 30 is also small. Thereafter, as the temperature of the reforming catalyst gradually rises, the amount of methanol used in the partial oxidation reaction and steam reforming reaction increases, so even if the amount of methanol input is gradually increased, the unreacted methanol is excessively increased. There is no increase. Then, when the reforming catalyst almost reaches a temperature suitable for the steady operation state near the time t2, the unreacted methanol rapidly decreases. Further, since the amount of unreacted methanol condensed in the reforming catalyst immediately after startup is extremely small compared to the case of the comparative example, when the reforming catalyst almost reaches the temperature of the steady operation state near the time t2, the outlet The methanol concentration also decreases rapidly.
[0041]
The first embodiment further has the following advantages. The first advantage is that methanol as raw fuel can be saved because the amount of unreacted methanol discharged can be reduced. Therefore, the power generation efficiency of the fuel cell system 200 can be increased.
[0042]
A second advantage is that the time required for starting the reformer 30 can be shortened. That is, in the first embodiment, the outlet methanol concentration decreases earlier than in the comparative example, so that it is possible to start the power generation by supplying the high-quality fuel gas HRG to the fuel cell 40 from an earlier time point.
[0043]
The third advantage is that a rapid increase in temperature of the reforming catalyst due to the partial oxidation reaction can be prevented because the amount of methanol input immediately after the start of methanol injection is suppressed to a small amount. If methanol is excessively added to the reforming catalyst, the temperature of the reforming catalyst may rapidly increase due to the heat generated by the partial oxidation reaction. In addition, the reforming catalyst tends to be easily deteriorated in a high temperature and methanol rich environment. In the first embodiment, the amount of methanol input immediately after the start of methanol injection is suppressed to a small amount, so that a methanol-rich environment at high temperatures can be prevented and deterioration of the reforming catalyst can be prevented.
[0044]
A fourth advantage is that the amount of carbon monoxide generated at startup can be reduced. When the raw material gas rich in methanol is introduced into the reforming section 36, the methanol is decomposed as shown in the above equation (3) to generate carbon monoxide. In the first embodiment, since the amount of methanol in the raw material gas introduced into the reforming unit 36 at the time of startup is smaller than that in the conventional case, the amount of carbon monoxide generated at the time of startup can be reduced.
[0045]
FIG. 4 is an explanatory view showing the manner of controlling the amount of reforming material input in the second embodiment. In the second embodiment, the input amount of water is the same as that of the first embodiment, and the time change of the input amount of methanol is different from that of the first embodiment. That is, in the second embodiment, the value LM0 of the methanol input amount at time t1 is set to a value considerably lower than the value LM1 in the steady operation state (FIG. 4B). However, after time t1, the amount of methanol input increases substantially linearly and reaches a substantially constant value LM1 at time t2. The reciprocal value of the steam carbon ratio (S / C) also changes accordingly, and at time t1, a predetermined value higher than 0 (C / S) ₀ And then increases almost linearly to a substantially constant value (C / S) at time t2. ₁ Has reached. The graph of the outlet methanol concentration in the second example is omitted.
[0046]
Also in the second embodiment, the value of the reciprocal of the steam-carbon ratio (S / C) is set to an appropriate value (C / S) during steady operation during the period immediately after the start of methanol addition. ₁ Therefore, there are almost the same effects and advantages as the first embodiment.
[0047]
FIG. 5 is an explanatory diagram showing the manner of controlling the amount of reforming material input in the third embodiment. The third embodiment also differs from the first embodiment only in the change over time in the amount of methanol input. That is, in the third embodiment, during the period from time t1 to time t2, the amount of methanol input is maintained at a constant value LM0 that is lower than the value LM1 in the steady operation state, and at time t2, the value is LM1 in the steady operation state. It rises in steps. It can be understood that the value of the reciprocal of the steam carbon ratio (S / C) also changes accordingly (FIG. 5C). Note that such a step-like change is not limited to one time but may be performed a plurality of times.
[0048]
Also in the third embodiment, the value of the reciprocal of the steam-carbon ratio (S / C) is set to an appropriate value (C / S) during steady operation in the period immediately after the start of methanol addition. ₁ Is set smaller. Accordingly, the third embodiment has substantially the same effects and advantages as the first and second embodiments.
[0049]
The third embodiment is also common to the first and second embodiments in that the reciprocal value of the steam-carbon ratio (S / C) is monotonously increased. Here, a certain value “monotonously increases” means that the value does not substantially decrease, and there are only a period during which the value increases and a period during which the value is kept constant.
[0050]
However, in the third embodiment, the amount of methanol input and the steam / carbon ratio (S / C) change stepwise at time t2, so that the temperature of the reforming catalyst can be sufficiently increased by time t2. It may not be possible. Therefore, from the viewpoint of shortening the start-up time of the reformer, the value of the reciprocal of the steam carbon ratio (S / C) is continuously increased as in the first and second embodiments described above. A control method is preferred.
[0051]
As in the second and third examples, the reciprocal of the steam-carbon ratio (S / C) immediately after the start of methanol addition is a non-zero value (C / S). ₀ This initial value (C / S) ₀ Is preferably set to about ½ or less of an appropriate value in a steady operation state. For example, when the range of the proper value of the steam carbon ratio (S / C) in the steady operation state is about 1.5 to about 2.0, the range of the reciprocal number (C / S) is about 0.50 to about 2.0. 0.67. In this case, the reciprocal value (C / S) of the steam-carbon ratio (S / C) immediately after the start of methanol addition ₀ Is preferably about 0.25 or less. In this way, if the input amount immediately after the start of methanol injection is set to a relatively low value, the above-described effects and advantages of suppressing the amount of methanol input at startup can be more efficiently exhibited. is there.
[0052]
FIG. 6 is an explanatory view showing the manner of controlling the amount of reforming material input in the fourth embodiment. In the fourth embodiment, the time change of the amount of methanol input is the same as that of the first embodiment, but the time change of the amount of water input is different from that of the first embodiment. That is, in the fourth embodiment, the amount of water input at time t1 is set to a value LW0 lower than the value LW1 in the steady operation state, and the amount of water input increases linearly from time t1 to time t2. ing. It can be understood that the reciprocal value of the steam carbon ratio (S / C) also changes in a curved manner in accordance with this (FIG. 6C).
[0053]
Also in the fourth embodiment, the value of the reciprocal of the steam-carbon ratio (S / C) is set to an appropriate value (C / S) during steady operation during the period immediately after the start of methanol addition. ₁ Therefore, there are almost the same effects and advantages as the first to third embodiments.
[0054]
C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.
[0055]
C1. Modification 1:
As raw materials for the reformer, alcohols other than methanol, and various hydrocarbon fuels such as natural gas, gasoline, aldehyde, and ether can be used. That is, even when a raw fuel other than methanol is used, the ratio (C / S) of the number of moles of carbon C to the number of moles S of water in the raw fuel is changed when the reformer is started. The input amount of water or raw fuel may be controlled so as to be smaller than a predetermined appropriate value during steady operation of the mass device.
[0056]
In addition, gasoline contains a very large number of hydrocarbons having a boiling point in the range of about 40 ° C. to 220 ° C., but also contains a considerable amount of hydrocarbons having a boiling point of 100 ° C. or less. Therefore, the effects of the present invention can be obtained even in a gasoline reformer. However, the present invention is particularly effective when applied to a reforming apparatus for raw fuel mainly composed of a hydrocarbon compound having a boiling point lower than that of water, such as a methanol reforming apparatus.
[0057]
C2. Modification 2:
In each of the above-described embodiments, the period from the time t1 to the time t2 is used as the start-up period of the reformer 30. However, the definition of the start-up period of the reformer 30 is quite arbitrary. For example, it is possible to define the starting period up to a certain time after time t2, and it is also possible to define the starting period until the time when the reforming catalyst reaches a certain temperature. Therefore, in the present invention, the ratio (C / S) of the number of moles C of carbon in the raw fuel to the number of moles S of water in at least a part of the period when the reformer is started up is as described above. It only needs to be controlled. However, as described in the above embodiments, it is preferable to apply the present invention in the initial period of the reformer starting period including the starting time of the raw fuel input to the reformer.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing the configuration of a fuel cell system as a first embodiment of the present invention.
FIG. 2 is an explanatory view showing a state of control of the amount of reforming material input in a comparative example.
FIG. 3 is an explanatory diagram showing a state of reforming raw material input amount control in the first embodiment.
FIG. 4 is an explanatory diagram showing a state of control of the amount of reforming material input in the second embodiment.
FIG. 5 is an explanatory diagram showing a state of reforming raw material input amount control in the third embodiment.
FIG. 6 is an explanatory diagram showing a state of reforming raw material input amount control in the fourth embodiment.
[Explanation of symbols]
10 ... Raw fuel tank
20 ... Water tank
30 ... reformer
32 ... Vaporizer
34 ... heating unit
36 ... reforming section
36a ... mixing chamber
38 ... Selective oxidation part
40 ... Fuel cell
42 ... Fuel gas passage
44 ... Air passage
46 ... Air pump
50 ... Controller
51, 53, 55 ... Flowmeter
52, 54, 56 ... pump
64, 66 ... air supply section
64a, 66a ... air pump
64b, 66b ... Pressure gauge
64c, 66b ... motorized valve
92 ... Temperature sensor
94. Oxygen concentration sensor
96 ... Carbon monoxide concentration sensor
98 ... Raw fuel sensor (methanol concentration sensor)
102 ... Raw fuel supply path
104, 106 ... Branching channel
108 ... Water supply channel
110 ... flow path
112 ... Fuel gas flow path
114 ... discharge path
200 ... Fuel cell system

Claims (5)

A fuel reformer for producing hydrogen-rich fuel gas from a raw fuel containing a hydrocarbon compound,
A vaporization unit that vaporizes both the raw fuel and water used for a steam reforming reaction of the raw fuel, a steam reforming unit that reforms the raw fuel using a steam reforming reaction, and the steam A reformer in which a selective oxidation unit that oxidizes carbon monoxide contained in the reformed gas reformed in the reforming unit using a selective oxidation reaction is arranged in this order ;
A raw fuel supply unit for supplying the raw fuel to the vaporization unit ;
A water supply unit for supplying water to be available before Kisui steam reforming reaction in the vaporizing part,
The mole number C of carbon contained in the raw fuel supplied from the raw fuel supply section and the mole number of water supplied from the water supply section in at least a part of the period when the reformer is started. By making the ratio (C / S) value with S smaller than a predetermined appropriate value during steady operation of the reformer, it passes through the vaporization section, the steam reforming section, and the selective oxidation section. A control unit for controlling the raw fuel supply unit and the water supply unit so as to reduce unreacted raw fuel discharged after
A fuel reformer characterized by comprising: The fuel reformer according to claim 1, wherein
The control unit controls the raw fuel supply unit and the water supply unit so that the value of the ratio (C / S) continuously increases when the reformer is started. . The fuel reformer according to claim 2, wherein
The fuel reformer is a fuel reforming apparatus in which a main component is a hydrocarbon compound having a boiling point lower than that of water. The fuel reformer according to claim 3, wherein
The fuel reforming apparatus, wherein the raw fuel is methanol. A vaporization section that vaporizes both the raw fuel and water used for a steam reforming reaction of the raw fuel, a steam reforming section that reforms the raw fuel using a steam reforming reaction, and the steam reforming A selective oxidation unit that oxidizes carbon monoxide contained in the reformed gas reformed in the mass part using a selective oxidation reaction, and a control method of the reformer arranged in this order ,
At least part of the period at the start of the reformer, the value of the ratio (C / S) of the moles S moles C and water carbon in the raw fuel supplied to the reformer The unreacted raw fuel discharged after passing through the vaporization section, the steam reforming section, and the selective oxidation section is reduced by making it smaller than a predetermined appropriate value during steady operation of the reformer. as to the control method characterized by controlling the supply amount of the raw fuel and water.

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