JP5764341B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system having both a high temperature installation type first desulfurizer and a low temperature installation type second desulfurizer for desulfurizing a raw material gas as an odorant containing a sulfur compound.

  Patent Document 1 discloses a desulfurizer for LPG. This desulfurizer is divided into two, a room temperature desulfurizer and a high temperature (> 100 ° C.) desulfurizer. Moreover, the desulfurizer for normal temperature is arranged on the upstream side, and is used for sulfur compounds (TBM and DMS) that are contained in the raw material gas as an odorant and are relatively easy to desulfurize. The high-temperature desulfurizer is disposed on the downstream side of the normal-temperature desulfurizer, and adsorbs LPG-specific sulfur compounds (such as COS), and uses a metal oxide such as Ni.

  According to Patent Document 2, the configuration is basically the same as that of Patent Document 1, and it is divided into a normal temperature desulfurizer and a high temperature desulfurizer. The high-temperature desulfurizer is set to an operating temperature of 50 ° C. or higher. The desulfurization agent of the high-temperature desulfurizer is considered to be for LPG. According to Patent Document 3, a combination of two desulfurization methods (desulfurizer), that is, a normal temperature desulfurizer and a hydrogenation type desulfurizer (high temperature), the desulfurization effect due to hydrogenation at the time of start-up is insufficient. Make up with room temperature desulfurizer.

JP 2006-111766 A JP 2006-265480 A Japanese Patent Laid-Open No. 5-114414

  According to Patent Documents 1 to 3, it is not a technique related to maintenance such as replacement of the first desulfurizer and the second desulfurizer that are used together.

  By the way, the raw material gas (city gas) supplied from the gas company may contain moisture. The desulfurizing agent generally uses a porous material such as zeolite or activated carbon, and is used in a temperature environment at room temperature to adsorb and desulfurize a sulfur compound. However, the so-called low-temperature desulfurization agent based on a porous material has the advantage of low cost, but it is included in the raw material gas when desulfurizing a high dew point raw material gas containing a relatively large amount of water vapor. It has the property of adsorbing water vapor preferentially over sulfur compounds. As a result, in the case of desulfurizing a raw gas with a high dew point, the adsorption ability for adsorbing a sulfur compound contained in the raw gas is reduced, and the desulfurization effect may be excessively reduced (see FIG. 2). . The dew point refers to a temperature at which dew condensation occurs when the raw material gas is cooled. If it is a high dew point, the amount of water vapor is relatively large, and if it is a low dew point, the amount of water vapor is relatively small.

  Generally, low dew point raw material gas with less water vapor is supplied in the industry. However, the amount of water vapor contained in the raw material gas increases due to gas works or piping, and the raw material gas often has a high dew point. Here, due to the water vapor contained in the raw material gas having a high dew point, the desulfurization agent may reduce the adsorption ability for adsorbing the sulfur compound of the raw material gas, and the desulfurization effect of the desulfurization agent may be reduced. In order to avoid this problem, it is necessary to increase the use amount of the desulfurization agent more than necessary, which increases the cost and enlarges the size of the fuel cell system, which is impractical.

  The present invention has been made in view of the above circumstances, and when desulfurizing a low dew point raw material gas having a low water vapor, and also when desulfurizing a high dew point raw material gas containing a large amount of water vapor. , Sulfur compounds contained in the raw material gas can be desulfurized satisfactorily, thereby responding to changes in the dew point of the raw material gas, and in addition, maintenance related to the first and second desulfurizers (desulfurizing agent replacement, regeneration, repair) It is an object of the present invention to provide a fuel cell system for informing information on (including).

The inventor has been intensively developing a desulfurization apparatus for a fuel cell system. And this inventor paid attention to (i) (ii).
(I) In the industry, generally, a raw material gas having a relatively low dew point (for example, −20 ° C. or lower) is supplied. However, raw gas with a relatively high dew point is often supplied for various reasons such as gas construction and piping.
(Ii) A general desulfurization agent easily adsorbs water vapor contained in the raw material gas, and therefore, adsorption sites present in the desulfurization agent are taken away by the water vapor, making it difficult to adsorb sulfur compounds contained in the raw material gas. However, even as a desulfurization agent having water vapor damage as described above, in a high temperature environment (for example, 40 ° C. or higher), it becomes difficult to adsorb water vapor, and therefore the influence of water vapor is reduced, and the desulfurization ability is easily maintained. The present invention has been completed based on such attention.

(1) In other words, the fuel cell system according to claim 1 includes: (i) a fuel cell having an anode supplied with anode gas and a cathode supplied with cathode gas; and a cathode supplying cathode gas to the cathode of the fuel cell. A gas passage, a reformer that reforms the source gas to generate anode gas, a gas conveyance source that supplies the source gas to the reformer, and a first desulfurizer and a second desulfurizer that desulfurize the source gas A raw material gas passage, an anode gas passage for supplying the anode gas generated by the reformer to the anode of the fuel cell, and a control unit,
(Ii) The first desulfurizer is disposed upstream of the second desulfurizer, is installed in a relatively high temperature first environment, and is a second desulfurizer for a relatively high dew point raw material gas. Desulfurizer with better desulfurization performance,
(Iii) The second desulfurizer is installed in a second environment that is relatively cooler than the first environment, and has a desulfurization performance with respect to a raw gas having a relatively low dew point and a relatively high dew point. It is a desulfurizer that lowers the desulfurization performance relative to the raw material gas with a relatively low dew point,
(Iv) The control unit is information on maintenance related to the first desulfurizer and the second desulfurizer based on the dew point of the raw material gas flowing through the raw material gas passage and the integrated amount of raw material gas flowing through the raw material gas passage from the reference time. Is notified.

  The source gas is usually supplied as a low dew point gas (for example, −20 ° C. or lower dew point). However, there is a high possibility that the gas is supplied as a high dew point gas (for example, + 20 ° C. dew point or higher) due to gas construction or piping. In this case, the low-temperature installation type desulfurization agent may deteriorate in a short period of time due to moisture, and the sulfur compound contained as a odorant in the raw material gas may flow into the reformer and the like, possibly reducing the durability of the reformer and the like. is there. On the other hand, since the first desulfurizer of high temperature installation type has a desulfurization performance with respect to the raw material gas of relatively high dew point than the second desulfurization apparatus of low temperature installation type, Even if it is a case where it supplies, the desulfurization effect can be acquired favorably. Normally, a raw gas with a low dew point is supplied, but a second low-temperature desulfurizer having good desulfurization performance with respect to a raw gas with a relatively low dew point is a first high-temperature installed type desulfurizer. Since the desulfurizer is also provided, the desulfurization performance can be secured even for the low dew point raw material gas by providing the second desulfurizer for the shortage in the first desulfurizer.

  Here, the high temperature of the high temperature installation type and the low temperature of the low temperature installation type mean the relative temperature. The high-temperature installation type first desulfurizer is installed at a relatively higher temperature than the low-temperature installation type second desulfurizer, and in a temperature range of, for example, 50 ° C. to 300 ° C. inside the casing of the fuel cell system. Be placed. On the other hand, the low-temperature installation type second desulfurizer is installed in a relatively lower temperature environment than the first desulfurizer inside the casing of the fuel cell system.

  In addition, when desulfurizing the raw material gas having a low dew point only with the high temperature installation type first desulfurizer, there is the following problem. In order to solve the problem, in addition to the first desulfurizer, the low temperature installation type first gas generator is used. Two desulfurizers are preferably provided. When desulfurizing a raw material gas having a low dew point, the desulfurization efficiency is generally better as the temperature of the desulfurizing agent is lower. Accordingly, when the low dew point source gas is desulfurized only by the high temperature installation type first desulfurizer, the desulfurization efficiency is not always sufficient, and there is a problem that the amount of the desulfurizing agent used in the first desulfurizer needs to be increased. . In this case, there is a problem that the amount of heat released from the first desulfurizer increases, the heat loss of the system increases, and the exhaust heat recovery efficiency decreases. Furthermore, the first desulfurizing agent used for the high temperature installation type first desulfurizer is often more expensive than the second desulfurization agent used for the low temperature installation type second desulfurization device in the general market.

However, according to the fuel cell system of the first aspect, both the high temperature installation type first desulfurizer and the low temperature installation type second desulfurizer are provided. The high dew point source gas (relatively more water vapor) is mainly shared by the high temperature installation type first desulfurizer, and the low dew point source gas (relatively less water vapor) is used in the low temperature installation type first desulfurizer. By mainly sharing with the two desulfurizers, the amount of the first desulfurizing agent having a high cost can be reduced as much as possible, and the cost can be reduced. Furthermore, the usage amount of the first desulfurizing agent and the second desulfurizing agent as a whole can be reduced, and the system can be miniaturized. As described above, according to the fuel cell system of the first aspect, when desulfurizing a low dew point raw material gas with less water vapor, further, when desulfurizing a high dew point raw material gas containing a large amount of water vapor. Also, desulfurization can be performed satisfactorily. Further, by providing the first desulfurizer upstream of the second desulfurizer, the second desulfurizer adsorbs moisture to the high dew point raw material gas, but the second desulfurizer is more than the first desulfurizer 100. Since it is arrange | positioned downstream, adsorption | suction of a sulfur compound is suppressed to a 2nd desulfurizer. Therefore, it is estimated that the second desulfurizer 200 is kept in a new state.

  By the way, as the power generation operation time of the system becomes longer and the integrated flow amount of the raw material gas flowing to the reformer through the raw material gas passage increases, the first desulfurizing agent of the first desulfurizer and the second desulfurizer of the second desulfurizer are increased. The desulfurization agent deteriorates. Furthermore, if the dew point of the raw material gas is high, the moisture contained in the raw material gas is large, so that the lifetimes of the first desulfurizer and the second desulfurizer are shortened. In particular, the low-temperature installation type second desulfurizer has a greater deterioration in desulfurization performance than the first desulfurizer with respect to a high dew point raw material gas. Therefore, according to the present invention, the control unit includes the first desulfurizer and the second desulfurizer based on the dew point of the raw material gas flowing through the raw material gas passage and the integrated flow amount of the raw material gas flowing through the raw material gas passage from the reference time. Information related to maintenance is notified. Maintenance includes any one of replacement of the desulfurizer itself and replacement of the desulfurization agent mounted on the desulfurizer. Replacement includes regeneration and repair.

  The reference time generally refers to the time when the fuel cell system is installed, the time when the accumulated flow amount of the raw material gas flowing through the raw material gas passage is started, or the time when the starting time can be substantially estimated. In this case, the time when a fuel cell system equipped with a desulfurizer in a new state (substantially including a new one) is newly installed, and the start time when the raw material gas is distributed to the desulfurizer in a new state (substantially including a new one) Alternatively, when the desulfurizer is replaced (including regeneration), the replacement time (regeneration time) is exemplified. Examples of the notification include alarming a maintenance signal on an alarm device, displaying a maintenance signal on a display unit, and stopping the operation of the system.

  (2) According to the fuel cell system of claim 2, when the dew point of the raw material gas flowing through the raw material gas passage is equal to or higher than the specified dew point, the control unit integrates the amount of raw material gas flowing through the raw material gas passage from the reference time. Based on this, the maintenance information about the maintenance regarding the first desulfurizer and the second desulfurizer is notified. When the dew point of the raw material gas is equal to or higher than the specified dew point, not only the second desulfurizer but also the first desulfurizer easily deteriorates, and the life of the desulfurizing agent is shortened. In this case, the sulfur compound that has not been removed may flow into the reformer. Therefore, the maintenance information for exchanging both the first desulfurizer and the second desulfurizer is notified.

  (3) According to the fuel cell system of claim 3, when the dew point of the raw material gas flowing through the raw material gas passage is equal to or higher than the specified dew point, the control unit is configured to integrate the amount of raw material gas flowing through the raw material gas passage from the reference time. Based on the above, the maintenance information for replacing the first desulfurizer is notified without replacing the second desulfurizer. When the dew point of the source gas is equal to or higher than the specified dew point, the second desulfurizer often does not substantially exhibit the desulfurization effect. Therefore, the maintenance information for replacing (including regeneration and repair) the first desulfurizer that exhibits the desulfurization effect is notified without replacing the second desulfurizer that does not exhibit the desulfurization effect.

  (4) According to the fuel cell system according to claim 4, when the dew point of the raw material gas flowing through the raw material gas passage is less than the specified dew point, the control unit integrates the amount of the raw material gas flowing through the raw material gas passage from the reference time. Based on the above, the maintenance information for replacing the desulfurizing agent of the second desulfurizer without replacing the desulfurizing agent of the first desulfurizer is notified. When the dew point of the raw material gas is less than the specified dew point, the desulfurization performance of the second desulfurizer is high. Therefore, the maintenance information for replacing the low-cost second desulfurizer (including regeneration and repair) is notified without replacing the expensive first desulfurizer.

  (5) Depending on circumstances such as piping work, the dew point of the source gas may change before and after the specified dew point. In this case, the lifetimes of the first desulfurizer and the second desulfurizer are affected by the integrated flow rate of the source gas below the specified dew point and the integrated flow rate of the source gas above the specified dew point. Therefore, according to the fuel cell system of claim 5, when the dew point of the source gas flowing through the source gas passage changes before and after the specified dew point, the control unit integrates the source gas less than the specified dew point flowing through the source gas passage. Maintenance information about maintenance related to the first desulfurizer and the second desulfurizer is notified based on the total circulation amount obtained by summing the circulation amount and the integrated circulation amount of the source gas equal to or higher than the specified dew point flowing through the source gas passage.

  (6) According to the fuel cell system of the sixth aspect, the first desulfurizer, the second desulfurizer, and the flow meter are arranged in this order from upstream to downstream in the raw material gas passage. The desulfurizing agent generally has an adsorption or desorption characteristic of hydrocarbon groups (for example, methane, butane, etc.) with respect to temperature. For this reason, when the temperature of the desulfurizing agent is changed at the time of starting / stopping the system, or when the load of the system is changed, the hydrocarbon group as the main component of the raw material gas may be adsorbed or desorbed from the desulfurizing agent. In particular, when it is installed in a high temperature range like the first desulfurizer, the influence is even greater. For this reason, when the flow meter is upstream of the first desulfurizer as in the prior art, the hydrocarbon group (for example, methane, butane, etc.) is used in the desulfurizer although the flow rate of the raw material gas is measured by the flow meter. As a result, the actual flow rate of the raw material gas supplied to the reformer may fluctuate. That is, the hydrocarbon group is adsorbed or desorbed in the first desulfurizer, and the actual flow rate of the raw material gas actually supplied to the reformer may be insufficient or excessive. Here, when the raw material gas is insufficient, the fuel cell may be deteriorated due to the shortage of the raw material gas. In addition, when the raw material gas becomes excessive, the reformer or fuel cell due to coking deterioration of the reforming catalyst or abnormally high temperature due to a decrease in the molar ratio (S / C) of water vapor to the raw material gas in the reformer. There is a risk of accelerating the deterioration of the material. For this reason, it is preferable to install a flow meter downstream from the first desulfurizer having the characteristic of adsorbing or desorbing hydrocarbon groups depending on the temperature.

  Furthermore, when the flow meter is installed downstream from the high temperature installation type first desulfurizer, the raw material gas that has passed through the first desulfurizer has heat, and the temperature of the raw material gas is higher than the heat resistance temperature of the flow meter. Therefore, it is not preferable for extending the life of the flow meter. Therefore, according to the fuel cell system of the sixth aspect, the first desulfurizer, the second desulfurizer, and the flow meter are installed in this order. In this way, the raw material gas is flowed in the order of the high temperature installation type first desulfurizer → the low temperature installation type second desulfurizer → the flow meter. As a result, the heat of the raw material gas that has passed through the high-temperature first desulfurizer is transferred by the second desulfurizer, and is dissipated in the second desulfurizer. For this reason, the temperature of the raw material gas flowing into the flow meter can be lowered as much as possible, and the problem of heat resistance of the flow meter can be solved, which is advantageous for extending the life of the flow meter. Moreover, since the raw material gas that has passed through the first desulfurizer has a small amount of heat, it is possible to sufficiently lower the temperature of the raw material gas by heat radiation in the second desulfurizer. Here, even when adsorption or desorption of hydrocarbon groups (such as methane or butane) occurs in the desulfurizer, and as a result, the actual flow rate of the raw material gas supplied to the reformer fluctuates, The first desulfurizer of the mold, the second desulfurizer of the low temperature installation type, and the flow meter are flowed in this order.

According to the present invention, the first desulfurizer of the high temperature installation type and the second desulfurization apparatus of the low temperature installation type are provided in series downstream of the first desulfurizer. Furthermore, even when a high dew point raw material gas containing a large amount of water vapor is desulfurized, the sulfur compound contained in the raw material gas can be well desulfurized. Thereby, it can respond to the change of the dew point of source gas.

  When the power generation operation period of the system becomes longer and the integrated flow amount of the raw material gas flowing through the raw material gas passage increases, the deterioration of the first desulfurizer and the second desulfurizer proceeds. Furthermore, if the dew point of the raw material gas is low, the amount of water vapor and moisture contained in the raw material gas are small, and the lifetimes of the first desulfurizer and the second desulfurizer are long. When the dew point of the raw material gas is high, the amount of water vapor and moisture contained in the raw material gas are large, and thus the lifetimes of the first desulfurizer and the second desulfurizer are short. In particular, the desulfurization performance of the second desulfurizer is much lower than that of the first desulfurizer with respect to the raw material gas having a high dew point. Therefore, the control unit relates to maintenance related to the first desulfurizer and the second desulfurizer based on the level of the dew point of the raw material gas flowing through the raw material gas passage and the integrated amount of raw material gas flowing through the raw material gas passage from the reference time. Broadcast information. For this reason, the presence or absence of maintenance (including replacement, regeneration, and repair) can be notified appropriately for the first desulfurizer and the second desulfurizer.

1 is a conceptual diagram illustrating a fuel cell system according to Embodiment 1. FIG. It is a graph which shows the relationship between the dew point of raw material gas, the temperature of a desulfurization agent, and the lifetime (relative value) regarding a 1st desulfurization agent and a 2nd desulfurization agent. It is a conceptual diagram which shows the form of replacement | exchange of a desulfurizer. It is a conceptual diagram which shows the form of replacement | exchange of a desulfurizer when source gas changes from a low dew point to a high dew point. It is a conceptual diagram which shows the form of replacement | exchange of a desulfurizer when source gas changes from a low dew point to a high dew point. It is a flowchart which a control part performs. It is a conceptual diagram which shows a fuel cell system concerning a reference example . It is a conceptual diagram which shows the state which concerns on another embodiment and the 1st desulfurizer is adjacently installed in the electric power generation module. It is a conceptual diagram which concerns on another embodiment and shows the state by which the 1st desulfurizer is arrange | positioned. It is a conceptual diagram which shows the state which concerns on another embodiment and the 1st desulfurizer is arrange | positioned. It is a conceptual diagram which shows a fuel cell system in connection with an application form.

Examples of the base material of the desulfurizing agent accommodated in the high temperature installation type first desulfurizer and the low temperature installation type second desulfurizer include zeolites, zeolites supporting metals such as transition metals, and porous materials such as activated carbon. The first desulfurizing agent of the first desulfurizer often contains a metal such as a transition metal. In this case, a form having both chemical adsorption and chemical adsorption may be used. Examples of the metal include at least one of silver, copper, gold, rhodium, palladium, iridium, ruthenium, osmium, nickel, iron, chromium, and molybdenum, and an alloy containing two or more of these. Is done. The first desulfurizing agent used in the first desulfurizer preferably contains the above-described metal in a mass ratio of 0.5 to 40% when the first desulfurizing agent is 100%. Zeolite
It is a general term for aluminosilicates having voids in the crystal structure, and may be natural zeolite or artificial zeolite. The desulfurizing agent physically adsorbs not only sulfur compounds (for example, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide) contained in the raw material gas but also water vapor and HC contained in the raw material gas. The adsorption capacity of the desulfurizing agent varies depending on the type of adsorbate such as water vapor and the temperature of the desulfurizing agent, and is easily damaged by water vapor particularly in the normal temperature region. Here, in the desulfurization agent, among substances that obstruct the adsorption of sulfur compounds contained in the raw material gas, it is considered that the water vapor contained in the raw material gas has the greatest influence. Therefore, when a raw material gas having a low dew point (for example, 0 ° C. or lower, −10 ° C. or lower) is desulfurized with a desulfurizing agent, the content of water vapor contained in the raw material gas is small and the influence of water vapor is small. The ability to adsorb sulfur compounds contained therein is effectively exhibited. However, when the high dew point raw material gas is passed through the second desulfurizer in the normal temperature region, the amount of water vapor contained in the raw material gas is increased. 2 The ability of the desulfurizing agent to adsorb sulfur compounds is drastically reduced. Even if it is the 2nd desulfurization agent which has such a property, if a temperature environment becomes high temperature (for example, 40 degreeC or more, 50 degreeC or more, 230 degrees C or less), the water vapor | steam damage in a desulfurization agent will recover, As a result, desulfurization The ability is restored.

(Embodiment 1)
FIG. 1 shows a first embodiment. The fuel cell system includes a fuel cell 1 having an anode 10 and a cathode 11, a cathode gas passage 70 for supplying a cathode gas (oxygen-containing gas such as air) to the cathode 11 of the fuel cell 1, and reforming a raw material gas. A reformer 2A for generating an anode gas (hydrogen-containing gas or hydrogen gas), and a source gas passage 6 having a pump 60 functioning as a gas conveyance source for supplying the reformer 2A with the source gas desulfurized; The anode gas passage 73 that supplies the anode gas generated in the reformer 2A to the anode 10 of the fuel cell 1 and the heat insulation wall 19 that accommodates the anode gas passage 73, the reformer 2A, and the fuel cell 1 are provided. The power generation module 18 is formed by the reformer 2 </ b> A, the fuel cell 1, and the heat insulation wall 19. A water supply passage 8 for supplying water for reforming or steam is connected to the reformer 2A. The reformer 2A includes an evaporating unit that generates water vapor and a reforming unit that reforms fuel using the water vapor.

  As shown in FIG. 1, the raw material gas passage 6 includes a shut-off valve 69, a high temperature installation type first desulfurizer 100 that accommodates the first desulfurization agent, and a low temperature installation type that accommodates the second desulfurization agent, from upstream to downstream. The second desulfurizer 200 and the flow meter 300 for measuring the flow rate of the raw material gas that has passed through the first desulfurizer 100 and the second desulfurizer 200 are provided in series in this order. The first desulfurizer 100 is installed in a relatively high temperature first environment (for example, a temperature environment of 50 ° C. or more and 220 ° C. or less). Specifically, the first desulfurizer 100 receives heat (heat) from the heat insulating wall 19 of the power generation module 18. In order to be able to receive heat of conduction and radiant heat), the outer wall surface of the heat insulating wall 19 is arranged adjacent to the outer wall surface in contact with or close to it.

  The first desulfurizer 100 accommodates a first desulfurizing agent having desulfurization performance even for a raw material gas having a relatively high dew point. Examples of the first desulfurizing agent include zeolite, but porous materials such as zeolite supporting a metal such as silver and copper, and activated carbon may be used. The second desulfurizer 200 is installed in a second environment that is relatively cooler than the first environment (for example, less than 0 to 50 ° C.), and is spaced apart from the high-temperature power generation module 18. The second desulfurizing agent of the second desulfurizer 200 has a desulfurization performance with respect to a raw gas having a relatively low dew point. In the second desulfurizer 200, the desulfurization performance is lowered with respect to the relatively high dew point source gas (relatively more water vapor) than the relatively low dew point source gas (relatively less water vapor). (See FIG. 2). An example of such a second desulfurizing agent is zeolite. Examples of the source gas include hydrocarbons.

  Generally, the raw material gas (for example, city gas (13A)) has a low dew point (for example, 0 ° C. or lower, −10 ° C. or lower, −20 ° C. or lower), and the water vapor contained in the raw material gas is a minute amount. . However, due to circumstances such as gas piping work and piping, the amount of water vapor contained in the raw material gas is increased, and there is a high possibility that a raw material gas having a high dew point (for example, + 20 ° C. or higher) is supplied. In this case, the desulfurizing agent is deteriorated in a short period of time, and a sulfur compound contained as a odorant in the raw material gas flows into the reformer 2A or the like, and there is a possibility that the durability of the reformer 2A or the like is lowered. On the other hand, the high-temperature installation type first desulfurizer 100 has good desulfurization performance even for a raw material gas having a relatively high dew point. For this reason, even if it is a case where the raw material gas of a high dew point is supplied, the desulfurization effect can be acquired favorably. Normally, a low dew point raw material gas is supplied to the raw material gas passage 6, but the second desulfurizer 200 having a good desulfurization performance with respect to the relatively low dew point raw material gas is the first desulfurizer. 100 is provided. For this reason, by providing the second desulfurizer 200 for the shortage in the first desulfurizer 100, the desulfurization performance can be ensured even for the raw material gas having a low dew point. In addition, when desulfurizing the raw material gas having a low dew point only with the high temperature installation type first desulfurizer 100, there are the following problems. In order to eliminate such problems, it is preferable to provide both the high temperature installation type first desulfurizer 100 and the low temperature installation type second desulfurizer 200.

That is, the case of desulfurization of low dew point of the feed gas is generally because better desulfurization efficiency as the temperature of the desulfurizing agent is not low, low dew point source gas only in the first desulfurizer 100 hot-premises In the case of desulfurization, there is a problem that the desulfurization efficiency is not sufficient and the amount of the first desulfurizing agent used in the first desulfurizer 100 needs to be excessively increased. However, according to this embodiment, by providing both the first desulfurizer 100 and the second desulfurizer 200, the high dew point raw material gas is mainly shared by the first desulfurizer 100, and the low dew point raw material gas is shared. By sharing with the second desulfurizer 200, the total amount of the first desulfurizing agent and the second desulfurizing agent as a whole can be reduced, and the system can be downsized.

Here, when the low dew point raw material gas is desulfurized only by the high-temperature installation type first desulfurizer 100, the desulfurization efficiency is not always sufficient, and therefore the first desulfurizing agent accommodated in the high-temperature first desulfurizer 100 is not sufficient. There is a problem that the usage amount needs to be increased. In this case, there is a problem that the amount of heat released from the first desulfurizer 100 increases, the heat loss of the system increases, and the exhaust heat recovery efficiency decreases. In addition, the first desulfurization agent used in the high temperature installation type first desulfurizer 100 is more expensive than the low temperature installation type desulfurization agent flowing in the general market. However, according to the present embodiment, both the high temperature installation type first desulfurizer 100 and the low temperature installation type second desulfurizer 200 are provided. The high dew point raw material gas is mainly shared by the first desulfurizer 100, and the low dew point raw material gas is mainly shared by the second desulfurizer 200, so that the high dew point raw material gas is used for the high temperature installation type first desulfurizer 100. The amount of high-cost desulfurization agent used can be reduced, and the cost can be reduced.

  In the case of the above configuration, the desulfurizing agent has an adsorption or desorption characteristic of hydrocarbon groups (for example, methane, butane, etc.) with respect to temperature. For this reason, when the desulfurizing agent temperature changes due to system start / stop, system load fluctuation, etc., hydrocarbon groups may be adsorbed or desorbed to the desulfurizing agent as the desulfurizing agent temperature changes. . In the case where the first desulfurizing agent is installed in the high temperature region as in the high temperature installation type first desulfurizer 100, the degree is further increased. For this reason, when the flow meter 300 is upstream of the desulfurizer as in the prior art, the hydrocarbon group (for example, methane, butane, etc.) is used in the desulfurizer although the flow rate of the raw material gas is accurately measured by the flow meter 300. ) Occurs, the flow rate of the raw material gas supplied to the reformer 2A may fluctuate. That is, hydrocarbon groups are adsorbed or desorbed in the desulfurizer, and the flow rate of the raw material gas actually supplied to the reformer may be excessive or insufficient. Here, when the raw material gas is insufficient, the fuel cell may be deteriorated due to the shortage of the raw material gas. In addition, when the raw material gas becomes excessive, the reformer or fuel cell due to coking deterioration of the reforming catalyst or abnormally high temperature due to a decrease in the molar ratio (S / C) of water vapor to the raw material gas in the reformer. There is a risk of accelerating the deterioration of the material. For this reason, it is preferable to install the flow meter 300 downstream of the first desulfurizer 100 having the characteristic of adsorbing or desorbing hydrocarbon groups depending on the temperature. However, when the flow meter 300 is installed downstream from the first desulfurizer 100, the raw material gas that has passed through the high temperature installation type first desulfurizer 100 has heat, and the raw material gas is supplied from the flow meter 300. Since the temperature tends to be higher than the heat-resistant temperature, there is a risk of causing the flow meter 300 to fail.

  Therefore, according to the present embodiment, as shown in FIG. 1, the flow meter 300 is installed downstream of both the first desulfurizer 100 and the second desulfurizer 200 in the raw material gas passage 6, and the reformer 2A or the like is installed. The source gas can be supplied stably. Furthermore, the heat of the raw material gas that has passed through the first desulfurizer 100 is transmitted and received by the second desulfurizer 200 by flowing the raw material gas in the order of the high temperature installation type first desulfurizer 100 → the low temperature installation type second desulfurizer 200. However, the second desulfurizer 200 can dissipate heat. For this reason, the temperature of the raw material gas flowing into the flow meter 300 that is easily affected by heat can be reduced as much as possible. In this case, the heat resistance problem of the flow meter 300 can be solved. In addition, since the heat amount which the raw material gas which passed the 1st desulfurizer 100 has is small, raw material gas can fully be low-temperature by the heat radiation in the 2nd desulfurizer 200. FIG. The pump 60 is preferably one that hardly generates pressure pulsation.

  As shown in FIG. 1, the source gas passage 6 is provided with a buffer 400 having a buffer chamber. In the raw material gas passage 6, the shutoff valve 69, the first desulfurizer 100, the second desulfurizer 200, the flow meter 300, the buffer 400, and the pump 60 are arranged in this order from upstream to downstream. The buffer 400 has a buffer chamber 401 that is a hollow chamber. The pump 60 conveys the raw material gas toward the reformer 2A of the power generation module 18 in the raw material gas passage 6, but there is a risk of generating pulsation of the pressure of the raw material gas. Therefore, as shown in FIG. 1, in the raw material gas passage 6, the first desulfurizer 100, the second desulfurizer 200, the flow meter 300, the buffer 400, and the pump 60 are arranged in series in this order. In this case, as shown in FIG. 1, the buffer 400 is disposed downstream of the flow meter 300 and upstream of the pump 60. The flow meter 300 is disposed immediately downstream of the second desulfurizer 200. That is, the buffer 400 is interposed between the pump 60 that causes pulsation and the flow meter 300 that does not want to receive pulsation. For this reason, the flow meter 300 is not easily affected by the pulsation of the pump 60. This is advantageous for stable operation of the system. In other words, as shown in FIG. 1, since the first desulfurizer 100 → second desulfurizer 200 → flow meter 300 → buffer 400 → pump 60 and check valve 500 are provided in series, the pulsation of the pump 60 is buffered. 400 can be absorbed. For this reason, the flow rate pulsation of the flow meter 300 can be suppressed. As a result, the output value of the flow meter 300 is stabilized, the stability in control is ensured, and the behavior in which the output value of the flow meter 300 due to pulsation deviates from the true value can be suppressed.

  Note that the check valve 500 may cause pulsation of the pressure of the raw material gas when activated. Therefore, as shown in FIG. 1, since the buffer 400 is interposed between the flow meter 300 and the check valve 500 (pump 60), the flow meter 300 is not easily affected by the pulsation caused by the pump 60 and the check valve 500. Become. In this case, the accuracy with which the flow meter 300 measures the flow rate of the source gas is ensured, which is advantageous for stable operation of the system.

  The first desulfurizer 100 is installed so as to be in contact with or close to the outer wall surface side of the cross-sectional wall 19 so that it can receive heat from the heat insulating wall 19 of the power generation module 18, and is in a specified temperature range (for example, 60 to 220 ° C. or 60 to 150 ° C.). On the other hand, the second desulfurizer 200 is installed in a relatively low temperature environment (0 ° C. or more and less than 50 ° C.) that is separated from the power generation module 18 inside the system casing. Here, the raw material gas flows through the first desulfurizer 100, so that the raw material gas is heated and supplied to the second desulfurizer 200. Since the amount of heat that the source gas has is several W, the temperature on the upstream side of the second desulfurizer 200 slightly increases. Here, the raw material gas is lowered to the internal temperature of the system casing by heat radiation in the second desulfurizer 200, and is sent to the flow meter 300, the buffer 400, the check valve 500, and the reformer 2 </ b> A of the power generation module 18. As a result, the temperature of the raw material gas entering the flow meter 300 is lowered to a temperature lower than the heat resistance temperature of the flow meter 300, and the system can be operated without causing a failure of the flow meter 300. Further, adsorption or desorption of hydrocarbon groups may occur in the first desulfurizer 100 due to the temperature change of the first desulfurization agent accommodated in the first desulfurizer 100 from the start to the stop of the system. In this regard, according to the present embodiment, the flow meter 300 is disposed downstream of the first desulfurizers 100 and 200, so that the raw material gas flowing into the power generation module 18 (the raw material gas after adsorption or desorption) is reduced. The flow rate per unit time can be accurately grasped. In this case, it is possible to suppress deterioration due to gas shortage in the power generation module 18.

  By the way, when the accumulated time of the power generation operation of the system becomes longer, the deterioration of the first desulfurizer 100 and the second desulfurizer 200 progresses as the integrated circulation amount of the raw material gas flowing through the raw material gas passage 6 increases. Furthermore, when the dew point of the raw material gas is high, the amount of water vapor and moisture contained in the raw material gas are large, and thus the lifetimes of the first desulfurizer 100 and the second desulfurizer 200 are short. In particular, the desulfurization performance of the second desulfurizer 200 is higher than that of the first desulfurizer 100 with respect to the raw material gas having a high dew point. Therefore, according to the present embodiment, the control unit 100X performs the first desulfurization based on the dew point of the raw material gas flowing through the raw material gas passage 6 and the integrated flow amount of the raw material gas flowing through the raw material gas passage 6 from the reference time. Information related to maintenance (including replacement, regeneration, and processing) related to the vessel 100 and the second desulfurizer 100 is notified. For this reason, the first desulfurizer 100 and the second desulfurizer 200 can be appropriately maintained.

  Examples of the notification include alarming a maintenance signal on an alarm device, displaying a maintenance signal on a display unit, and stopping the operation of the system. The reference time generally refers to a time when the accumulated flow amount of the raw material gas flowing through the raw material gas passage starts or when it can be substantially estimated as the starting time. The time when a new fuel cell system equipped with a desulfurizer in a new state (substantially including a new one) is installed, the start time when the raw material gas is distributed to the desulfurizer in a new state (substantially including a new one), or When the desulfurizer is replaced, the replacement time is exemplified. The integrated circulation amount is obtained by the control unit 100X based on a signal from the flow meter 300.

(Embodiment 2)
FIG. 2 shows a second embodiment. Since this embodiment basically has the same configuration and the same function and effect as the first embodiment, FIG. 1 is applied mutatis mutandis. FIG. 2 shows the dew of the source gas when the temperatures of the first desulfurizing agent used in the first desulfurizer 100 and the second desulfurizing agent used in the second desulfurizer 200 are 40 ° C. and 70 ° C. The relationship between the point and the life of the desulfurizing agent is shown. In FIG. 2, a characteristic line AH shows a case where the temperature of the first desulfurizing agent is 70 ° C., and a characteristic line AL shows a case where the temperature of the first desulfurizing agent is 40 ° C. Characteristic line BH shows the case where the temperature of the second desulfurizing agent is 70 ° C., and characteristic line BL shows the case where the temperature of the second desulfurizing agent is 40 ° C. When the dew point temperature of the raw material gas is relatively low, since the amount of water vapor contained in the raw material gas is small, any desulfurizing agent has a long life. As for the first desulfurizing agent, AH and AL have a relatively small difference and the influence of temperature is small, but it can be seen that the second desulfurizing agent has a longer BL life than BH and a longer desulfurizing agent temperature. In the region where the dew point is relatively high, both the first and second desulfurizing agents have shorter lifetimes than the low dew point. The life of the second desulfurizing agent is significantly reduced, whereas the life of the first desulfurizing agent is long. In particular, AH having a high desulfurizing agent temperature can maintain a long life. From the above, it is desirable to use the first desulfurizing agent for the first desulfurizer. Regarding the second desulfurizer, it is desirable to use a second desulfurization agent that has good desulfurization characteristics at low temperature and low dew point and is inexpensive. In addition, you may use a 1st desulfurization agent for a 2nd desulfurizer. The first desulfurizing agent shows good desulfurization characteristics even at low temperatures because AH and AL are not significantly different in the low dew point region, and has a longer life than the second desulfurizing agent in the same amount from the relative value of life. Therefore, it is shown that a small amount of desulfurizing agent may be used to provide the same lifetime. From the above, it is desired to select a desulfurization agent from the downsizing by the required desulfurization agent amount and the cost (determined from unit price × capacity) in the total desulfurization agent amount. Note that when the dew point of the raw material gas is shifted from a high dew point to a low dew point for both the first and second desulfurizing agents, the sulfur adsorption capacity (lifetime) shown in FIG. ) Can be recovered.

(Embodiment 3)
FIG. 3 shows a third embodiment. Since this embodiment basically has the same configuration and the same function and effect as the first embodiment, FIGS. 1 and 2 apply mutatis mutandis. A first desulfurizing agent and a second desulfurizing agent having the characteristics shown in FIG. 2 are used. The first desulfurizer 100 has a life of 2.0 years from the reference time for a high dew point raw material gas and a life of 4.6 years for a low dew point raw material gas (normal raw material gas). Designed to be On the other hand, the second desulfurizer 200 is designed to have a life of 3.5 years from a reference time with respect to a low dew point raw material gas (normal raw material gas). In total, the first desulfurizer 100 and the second desulfurizer 200 have a lifetime of 8.1 years (3.5 + 4.6 = 8.1) at the initial installation of the system.

  The upper half A of FIG. 3 shows the case where the raw material gas having a low dew point is continuously supplied from the initial installation (reference time). A total life of 8.1 years is obtained in the initial installation. Therefore, after 8.1 years from the initial installation (reference time), only the second desulfurizer 200 effective for the low dew point raw material gas is replaced. Thereafter, only the second desulfurizer 200 is replaced (including regenerated) at a period of 3.5 years (corresponding to the lifetime of the second desulfurizer 200 when a low dew point raw material gas is supplied). This is because if the dew point is low, the second desulfurizer 200 exhibits a good desulfurization effect despite the low price.

  The first desulfurizer 100 has a lifetime of 4.6 years (when a low dew point raw material gas is supplied) from the initial installation. Since the first desulfurization agent of the first desulfurizer 100 is expensive, only the second desulfurizer 200 that is effective for desulfurization of the low dew point raw material gas is replaced. This makes it possible to exchange for 3.5 years and reduce the running cost required for desulfurization of the system.

  The lower half B of FIG. 3 shows a case where a raw material gas having a high dew point is continuously supplied from the initial installation (reference time). The first desulfurizer 100 is filled with a first desulfurizing agent having a life of two years when a raw gas having a high dew point (for example, + 20 ° C.) is supplied. On the other hand, as shown in FIG. 2, the second desulfurizer 200 has almost no desulfurization function with respect to the raw material gas having a high dew point. For this reason, the adsorption state of the odorant (sulfur compound) becomes saturated in the first desulfurizer 100 two years after the initial installation of the system. For this reason, only the first desulfurizer 100 is replaced after two years from the initial installation, and the second desulfurizer 200 is not replaced. As a first reason, the second desulfurizer 200 does not substantially have a desulfurization function with respect to a high dew point raw material gas. As a second reason, for cost reduction, as a third reason, as long as the first desulfurizer 10 on the upstream side has a desulfurization effect, the second desulfurizer 200 on the downstream side is in a state close to a new one, and the raw material gas If the dew point changes from a high dew point to a low dew point, the second desulfurizing agent 200 exhibits the desulfurization function again, and the second desulfurizer 200 is not replaced. Thus, when the raw material gas has a continuously high dew point, only the first desulfurizer 100 is replaced, and the second desulfurizer 200 that does not exhibit the desulfurization function is not replaced. The running cost required for desulfurization is reduced.

(Embodiment 4)
FIG. 4 shows a fourth embodiment. Since this embodiment basically has the same configuration and the same function and effect as the first embodiment, FIGS. 1 and 2 apply mutatis mutandis. In the present embodiment, although the low dew point raw material gas has been supplied from the initial installation of the system, the accumulated distribution amount of the low dew point raw material gas is less than one year (less than two years, relatively short period from the reference time). When the source gas changes from a low dew point to a high dew point.
Highly active sites in the first desulfurizing agent that adsorb sulfur compounds contained in a high dew point raw material gas with a relatively large amount of water vapor tend to adsorb sulfur compounds. Therefore, sulfur compounds contained in the raw material gas having a low dew point are easily adsorbed at the highly active site in the first desulfurizing agent. Therefore, the high active site in the first desulfurizing agent has a low dew point for one year. It is thought that sulfur compounds contained in the source gas are adsorbed. Therefore, the highly active site in the first desulfurizing agent treated with the low dew point raw material gas for one year can be calculated as the remaining one year, and the sulfur compound contained in the high dew point raw material gas can be adsorbed for only one year.
That is, when the lifetime of the first desulfurizer 100 with respect to the high dew point raw material gas is two years, which is the sum of the cumulative flow rate of the low dew point raw material gas and the cumulative flow rate of the high dew point raw material gas. In the first desulfurizer 100, it is determined that the desulfurization effect is saturated and the life is reached.
In the initial installation of the system, the first desulfurizer 100 has a lifetime of 4.6 years and the second desulfurizer 200 has a lifetime of 3.5 years for a low dew point raw material gas. Therefore, the total of the first desulfurizer 100 and the second desulfurizer 200 has a lifetime of 8.1 years (4.6 + 3.5 = 8.1). Even in the stage after one year, if the raw material gas has a low dew point, the first desulfurizer 100 has only adsorbed one year's worth of sulfur compounds . 4.6-1 = 3.6), and the total of the first desulfurizer 100 and the second desulfurizer 200 has a lifetime of 7.1 years (3.6 + 3.5 = 7.1). However, when the raw material gas changes from a low dew point to a high dew point after one year from the initial installation (reference time), the lifetime of the first desulfurizer 100 is one year remaining for the high dew point raw material gas, And the 2nd desulfurizer 200 hardly exhibits a desulfurization function. From this, it is considered that the first desulfurizer 100 has a remaining life of only one year for the raw material gas having a high dew point . For this reason, only the 1st desulfurizer 100 is replaced | exchanged, after driving | running for the remaining one year with the raw material gas of a high dew point. The second desulfurizer 200 that cannot exert the desulfurization effect on the high dew point raw material gas is not replaced.

  Here, although the moisture is adsorbed in the second desulfurizer 200, the second desulfurizer 200 is disposed downstream of the first desulfurizer 100, so that the adsorption of the sulfur compound is suppressed. Therefore, it is estimated that the second desulfurizer 200 is in a new state. In this case, if the raw material gas changes from a high dew point to a low dew point, the second desulfurizer 200 has a life of 3.5 years as it is, so the second desulfurizer 200 is not replaced. As a result, even when the raw material gas is changed from a low dew point to a high dew point on the way, only the first desulfurizer 100 needs to be replaced, and the second desulfurizer 200 need not be replaced. Therefore, the maintenance cost can be reduced.

(Embodiment 5)
FIG. 5 shows a fifth embodiment. Since this embodiment basically has the same configuration and the same function and effect as the first embodiment, FIGS. 1 and 2 apply mutatis mutandis. In the fifth embodiment, the low dew point raw material gas is supplied to the system in the initial stage of installation, and the accumulated distribution amount of the low dew point raw material gas is 2.5 years (two years or more) after the initial installation (reference time). The case where the source gas changes from a low dew point to a high dew point is shown. In the initial installation of the system, the first desulfurizer 100 has a lifetime of 4.6 years for a low dew point source gas. The second desulfurizer 200 has a lifetime of 3.5 years. Thus, there is a lifetime of 8.1 years as a total value of the first desulfurizer 100 and the second desulfurizer 200 with respect to the raw material gas having a low dew point. If the raw material gas has a low dew point at the stage after 2.5 years (relatively long period of time from the reference time) after the initial installation (reference time), the first desulfurizer 100 is 2.1 years (4.6 -2.5 = 2.1). The second desulfurizer 200 downstream from the first desulfurizer 100 still has a lifetime of 3.5 years.

However, this is not the case when the source gas changes from a low dew point to a high dew point after 2.5 years have passed since the initial installation .
Highly active sites in the first desulfurizing agent that adsorb sulfur compounds contained in a high dew point raw material gas with a relatively large amount of water vapor tend to adsorb sulfur compounds. Therefore, the highly active site in the first desulfurizing agent has a lifetime of two years of the sulfur compound contained in the low dew point raw material gas. Therefore, in 2.5 years of the low dew point raw material gas, all the highly active sites in the first desulfurizing agent adsorb sulfur compounds, and no high active sites remain to adsorb the sulfur compounds contained in the high dew point raw material gas. . For this reason, the first desulfurizer cannot adsorb the sulfur compound contained in the high dew point raw material gas, and the high dew point raw material gas enters the second desulfurizer as it is. Since the second desulfurizer cannot originally adsorb the sulfur compound in the raw material gas having a high dew point, the sulfur compound contained in the raw material gas may flow into the reformer 2A.

Therefore, at the stage where 2.5 years from initial installation (reference timing) has elapsed, when the raw material gas becomes high dew point from a low dew point, replace the first desulfurizer 100 that regarded as desulfurizing effect is saturated To do. In addition, since the sulfur compound for 2.5 years of the low dew point raw material gas is completely removed by the first desulfurizer and the second desulfurizer is considered to be in a new state, the second desulfurizer is not replaced.

After the replacement, if the raw material gas of a high dew point is supplied continuously, to replace only the first desulfurizer 100 every 2 years (life of the first desulfurizer 100 against the high dew point of the feed gas). If the source gas returns from the high dew point to the low dew point again , as explained in FIG. 3B, the second desulfurizer 200 is considered to be in a new state, so it should be used for 3.5 years. Can do. Thereby, the first desulfurizer 100 can be replaced at a low running cost while preventing the reformer from being deteriorated at the timing when the raw material gas is changed from the low dew point to the high dew point. In addition, according to each embodiment, it is preferable that the control unit 100X outputs an alarm when the replacement time comes. Examples of the alarm include an alarm that issues a warning signal to the alarm device 102 to a manufacturer, a user, and a maintenance person, or an alarm that stops the operation of the system. In this case, it is preferable to output an alarm to the alarm device 102 a predetermined time before the replacement time (for example, one month before).

(Embodiment 6)
FIG. 6 shows a sixth embodiment. Since this embodiment basically has the same configuration and the same function and effect as the first embodiment, FIGS. 1 and 2 apply mutatis mutandis. FIG. 6 shows a control flow executed by the microcomputer of the control unit 100X of this embodiment. When the fuel cell system is activated and the raw material gas is supplied to the system, the flowchart is started (step S1). First, the control unit 100X reads the dew point of the raw material gas detected by the dew point meter 510 (step S3), and then determines whether or not the dew point of the raw material gas is less than the predetermined value A1 (step S5). The prescribed value A1 is set within a range value of the dew point of the raw material gas sent by the gas company as a supply source, such as -15 ° C. dew point. If the dew point is less than the specified value A1 (YES in step S5), the control unit 100X determines that the source gas is a low dew point (the dew point is normal), and proceeds to step S7. In step S <b> 7, the control unit 100 </ b> X obtains the integrated circulation amount of the source gas from the reference time, and determines whether the integrated circulation amount is less than the predetermined amount BO. If the integrated flow amount is less than the predetermined amount BO (YES in step S7), it is determined that the first desulfurizing agent 100 and the second desulfurizer 200 still have the desulfurization capability, and the control unit 100X issues a command to continue the power generation operation. Output (step S9) and return to the main routine. When the integrated circulation amount is equal to or greater than the predetermined amount BO (NO in step S7), the control unit 100X determines that the desulfurization capability of the second desulfurization agent of the second desulfurizer 200 is a lifetime, and sets the second desulfurizer 200 to An alarm for replacement (including regeneration) is output to the alarm device 102 (step S11). Since the dew point is low, the second desulfurizer 200 is sufficient, and the first desulfurizer has a desulfurization capability, but the first desulfurizer 100 is expensive and is not replaced.

Here, the predetermined amount BO, for example, assuming that a lifetime of 8.1 years when the raw material gas of a low dew point (normal) is supplied to the system, the raw material gas during 8.1 years corresponding operation The accumulated distribution amount is set to BO . A control section 100X monitors the cumulative flow rate of the low dew point of the feed gas. When the integration flow rate of the raw material gas reaches 8.1 years (corresponding to the specified value BO), required Yes litho controller 100X of the exchange of the second desulfurizer 200 determines, in the second desulfurizer 200 second An alarm for exchanging the desulfurizing agent is output to the alarm device 102 (step S11). In this case, since the first desulfurizing agent in the first desulfurizer 100 is expensive, the running cost is high, and the desulfurizing capability is sufficient in the second desulfurizer 200, so the first desulfurizing agent is not replaced.

Furthermore, a case where the raw material gas is changed from a low dew point (less than the specified value A1) to a high dew point (A1 or higher) will be described. When the gas feedstock transitory in high dew point from a low dew point, in step S5, a dew point of the raw material gas is a prescribed value A1 or more, the control unit 100X raw gas is high dew point is determined (NO in step S5), and scan The process proceeds to step S13. In step S < b> 13, the control unit 100 </ b> X obtains an integrated circulation amount B < b> 2 of the raw material gas having a low dew point (less than the specified value A < b> 1) . Then, the control unit 100X determines whether or not the integrated circulation amount B2 is less than the predetermined value B1 (step S13). Here, the highly active site in the first desulfurizing agent that adsorbs the sulfur compound contained in the high dew point raw material gas having a relatively large amount of water vapor tends to adsorb the sulfur compound. Therefore, the sulfur compound contained in the low dew point raw material gas is adsorbed at the high activity site in the first desulfurizing agent to which the sulfur compound contained in the high dew point raw material gas is adsorbed. Therefore, when the sum of the integrated flow rate of the low dew point raw material gas and the integrated flow rate of the high dew point raw material gas is two years, which is the lifetime of the first desulfurizer 100 for the high dew point raw material gas, The desulfurizer 100 assumes that the desulfurization effect is saturated and has reached the end of its life .
Therefore, as the specified value B1, the amount of raw material gas that can be adsorbed and removed by the first desulfurizer 100 with the raw material gas having a high dew point is set. For example, when a high dew point raw material gas is supplied, in the case of a specification for maintenance of the system after two years, the cumulative distribution amount of the raw material gas corresponding to a two-year operation is set as the specified value B1. When the integrated flow rate B2 is equal to or greater than the specified value B1 (NO in step S13), it is considered that the first desulfurizer 100 has reached the end of its life with respect to the high dew point raw material gas. Therefore, an alarm for replacing the first desulfurizer 100 (including regeneration and repair) is output to the alarm device 102 (step S15), and the process returns to the main routine.

On the other hand, when it is determined in step S13 that the integrated flow amount B2 of the low dew point raw material gas is less than the specified value B1 (B2 <B1) , the control unit 100X changes the first desulfurizer 100 to the high dew point raw material gas. On the other hand, it is determined that there is still a desulfurization capability, and the process proceeds to step S17. In step S17, the operation is continued, and an integrated circulation amount B3 of the raw material gas having a high dew point (specified value A1 or more) is obtained . Further , a total value (B3 + B2) of the integrated circulation amounts B2 and B3 of the raw material gas having a low dew point (less than the specified value A1 ) is obtained. The control unit 100X determines whether or not the total value (B3 + B2) is less than the specified value B1 (step S17). When (B3 + B2) ≧ B1 (NO in step S17), the control unit 100X determines that the first desulfurizer 100 has reached the end of its lifetime (adsorbed for two years in the above example) with a high dew point raw material gas. Then, an alarm for exchanging only the first desulfurizer 100 is output (step S19). Here, the 2nd desulfurizer 200 hardly exhibits a desulfurization function with respect to the high dew point raw material gas. Since B2 <B1, and at least when the raw material gas is switched from a low dew point to a high dew point, the first desulfurizer 100 exhibits a high desulfurization function for the low dew point and high dew point raw material gas, About the 2nd desulfurizer 200, the sulfur compound (odorant) is hardly flowed in and it is judged that it is the same as a new article. For this reason, the second desulfurizer 200 is not replaced. Note that if the dew point of the raw material gas returns from a high dew point to a low dew point in the middle, the desulfurization capacity of the already installed second desulfurizer 200 will automatically return, so the second desulfurizer 200 is set for the number of years set initially. Of sulfur compounds can be adsorbed and removed.

If (B 3 + B2) <B1 (YES in step S17), the control unit 100X determines that the first desulfurizer 100 still has a desulfurization capability even with a raw material gas having a high dew point, and proceeds to step S7. Transition. Note that the flowchart shown in FIG. 6 is an example in which the prescribed value A1 and the prescribed value B1 related to the dew point are each shown at one level. However, the present invention is not limited to this, and by setting the specified value A1 and the specified value B1 related to the dew point stepwise or continuously, the number of maintenance can be reduced, and the maintenance cost and running cost can be reduced. For example, as shown in FIG. 2, when the dew point is 0 ° C. and 20 ° C., if the dew point is 0 ° C. compared to 20 ° C., the life of the desulfurizing agent is long. For this reason, the specified flow rate A1 is set at two levels of 0 ° C and 20 ° C. If the dew point is 20 ° C, it is exchanged for 2 years, and if the dew point is 0 ° C, it is exchanged for 4 years. By setting B1, it is possible to extend the maintenance period at the 0 ° C. dew point site compared to 20 ° C.

( Reference example )
FIG. 7 shows a reference example . The reference example basically has the same configuration and the same function and effect as the first embodiment. As shown in FIG. 7, the first desulfurizer 100 is disposed downstream of the second desulfurizer 200. That is, in the raw material gas passage 6, the second desulfurizer 200, the first desulfurizer 100, the cooling unit 600, and the flow meter 300 are arranged in this order from upstream to downstream. The boosting pump 60 may cause pulsation of the source gas. Therefore, a pulsation suppressing buffer 400 is provided between the flow meter 300 and the pump 60 in order to separate the pump 60 from the flow meter 300. In addition, when the flow meter 300 is weak to heat, the raw material gas that has passed through the high temperature installation type first desulfurizer 100 is radiated by the cooling mechanism 600 to cool the raw material gas. For this reason, the source gas cooled by the cooling unit 600 is supplied to the flow meter 300, and the flow meter 300 is protected from heat. Further, a buffer 400 is provided between the check valve 500 that functions as a check valve and the flow meter 300. For this reason, the flow meter 300 is suppressed from being affected by the operation of the check valve 500. Examples of the cooling unit 600 include a heat radiation fin method, a method in which cooling air strikes, and a cooling water and heat exchange method.

(Embodiment 7 )
FIG. 8 shows a seventh embodiment. As shown in FIG. 8, the high temperature installation type first desulfurizer 100 is in contact with the side surface 19 s (surface) of the heat insulating wall 19 of the above-described power generation module 18 (heating source) so as to be able to conduct heat, and is not illustrated. It is attached by a fixture. You may attach to the upper surface or lower surface of the cross-sectional wall 19. FIG. In the desulfurization chamber 101 of the first desulfurizer 100, a granular first desulfurization agent based on a zeolite-based porous material is accommodated. The heat of the power generation module 18 is transferred to the high temperature installation type first desulfurizer 100 by heat transfer and radiant heat. As shown in FIG. 8, the desulfurization chamber 101 of the first desulfurizer 100 is partitioned and bent a plurality of times by a plurality of partition plates 104 m that form a plurality of openings 103 m for U-turns. The raw material gas flowing in from the inlet 101i repeats a U-turn a plurality of times so as to meander, secures a desulfurization distance, and is discharged toward the reformer 2A from the outlet 101p. The thickness tx of the first desulfurizer 100 is preferably thinner than the width ty of the power generation module 18 and has a flat box shape. In this case, the heat receiving area from the side surface 19s (surface) of the heat insulating wall 19 of the power generation module 18 can be increased, which is advantageous in reducing the temperature variation of the first desulfurizing agent accommodated in the first desulfurizer 100. As in the case where the system has been stopped for a long period of time, the heat insulating wall 19 of the power generation module 18 may not be at a high temperature when the system is started. Therefore, as shown in FIG. 8, it is preferable to provide an electric heater 109 on the outer wall surface of the high temperature installation type first desulfurizer 100. When the system is started, the first desulfurizing agent of the high-temperature installation type first desulfurizer 100 is warmed by the electric heater 109 and set to a temperature environment of 50 ° C. or higher. When the heat insulating wall 19 of the power generation module 18 becomes hot, the electric heater 109 may be turned off. In some cases, the electric heater 109 may be eliminated. In addition, about each embodiment, it is preferable to provide an electric heater in the high temperature installation type first desulfurizer 100.

(Embodiment 8 )
FIG. 9 shows an eighth embodiment. As shown in FIG. 9, a high-temperature installation type first desulfurizer 100 in which a first desulfurization agent based on a porous material is accommodated in a pipe 78x forming a return path 78c of a hot water storage passage 78 through which hot water flows. Are parallel running while being in contact with each other at a joint 120 (for example, a welded portion or a brazed portion). The first desulfurizer 100 is heated to a high temperature environment of 50 ° C. or higher by the heat of hot water (for example, 50 ° C. to 95 ° C.) flowing through the hot water storage passage 78. Instead of the pipe 78x, an exhaust gas passage 75 through which high-temperature exhaust gas discharged from a reformer, a fuel cell, or the like flows may be used.

(Embodiment 9 )
FIG. 10 shows a ninth embodiment. As shown in FIG. 10, a pipe 78x that forms a return path 78c of a hot water storage passage 78 through which hot water flows is wound in a spiral shape around a high-temperature first desulfurizer 100 that contains a first desulfurizing agent. The first desulfurizer 100 is heated by the heat of hot water (for example, 50 ° C. to 95 ° C.) flowing through the hot water storage passage 78 and heated to a high temperature environment of 50 ° C. or higher. Instead of the pipe 78x, an exhaust gas passage 75 through which high-temperature exhaust gas discharged from a reformer, a fuel cell, or the like flows may be used.

(Application 1)
FIG. 11 shows the concept of application form 1. As shown in FIG. 11, the fuel cell system reforms fuel using the fuel cell 1, an evaporation unit 2 that evaporates liquid phase water to generate water vapor, and water vapor generated in the evaporation unit 2. And a tank 4 for storing liquid-phase water supplied to the evaporation unit 2, and a housing 5 for storing them. The fuel cell 1 includes an anode 10 and a cathode 11 that sandwich an ion conductor, and is, for example, a solid oxide type (operating temperature: 400 ° C. or more, for example) also called SOFC. The reforming unit 3 is formed by supporting a reforming catalyst on a carrier such as ceramics, and is adjacent to the evaporation unit 2. The reforming unit 3 and the evaporation unit 2 constitute a reformer 2A and are surrounded by a heat insulating wall 19 together with the fuel cell 1 to form a power generation module 18. In the power generation module 18, a combustion unit 105 that heats the reforming unit 3 and the evaporation unit 2 is provided. The anode exhaust gas discharged from the anode 10 side is supplied to the combustion unit 105 via the flow path 103. The cathode exhaust gas discharged from the cathode 11 side is supplied to the combustion unit 105 via the flow path 104. At startup, the combustion unit 105 burns the fuel supplied from the anode 10 with the cathode gas supplied from the cathode 11 and heats the evaporation unit 2 and the reforming unit 3. During the power generation operation, the combustion unit 105 burns the anode exhaust gas discharged from the anode 10 with the cathode exhaust gas discharged from the cathode 11 and heats the evaporation unit 2 and the reforming unit 3. The combustion unit 105 is provided with a combustion exhaust gas passage 75, and combustion exhaust gas including gas after combustion in the combustion unit 105 and unburned gas is released into the atmosphere through the combustion exhaust gas passage 75. A temperature sensor 33 that detects the temperature of the reforming unit 3 is provided. An ignition part 35 that is a heater for igniting is provided in the combustion part 105. The ignition unit 35 may be anything that can ignite the fuel. An outside air temperature sensor 57 that detects the temperature of the outside air is provided. Signals from the temperature sensors 33 and 57 are input to the control unit 100X. The control unit 100X outputs an alarm to the alarm device 102.

  During the power generation operation of the system, the reformer 2A is heated in the heat insulating wall 19 so as to be suitable for the reforming reaction. During the power generation operation, the evaporation unit 2 is heated so that water can be heated to steam. When the fuel cell 1 is of the SOFC type, the anode exhaust gas discharged from the anode 10 side and the cathode exhaust gas discharged from the cathode 11 side burn in the combustion unit 105, so that the reforming unit 3 and the evaporation unit 2 Heating is simultaneously performed inside the module 18. As shown in FIG. 11, the raw material gas passage 6 is configured to supply the raw material gas from the gas source 63 to the reformer 2 </ b> A, and includes the pump 60, the high temperature installation type first desulfurizer 100, and the low temperature installation type second. A desulfurizer 200, a flow meter 300, and a check valve 500 are provided.

  FIG. 11 merely shows a conceptual layout of an example of the fuel cell system. Actually, the first desulfurizer 100 contains a first desulfurizing agent based on a zeolite-based porous material having a metal such as silver, and is placed on the heat insulating wall 19 of the power generation module 18 (heating source). It is in contact so that it can receive heat. During operation of the system, the first desulfurizer 100 receives heat from the heat insulating wall 19 of the power generation module 18 and is heated to a high temperature region of, for example, 50 ° C. or higher and 230 ° C. or lower. The second desulfurizer 200 contains a second desulfurizing agent based on a zeolite-based porous material, is separated from the heat insulating wall 19 of the power generation module 18 (heating source), and is in a normal temperature range (for example, 0). It is installed in a temperature range from ℃ to less than 50 ℃. The cathode 11 of the fuel cell 1 is connected to a cathode gas passage 70 for supplying cathode gas (air) to the cathode 11. The cathode gas passage 70 is provided with a cathode pump 71 that functions as a transport source for transporting the cathode gas.

  As shown in FIG. 11, the housing 5 has an intake port 50 and an exhaust port 51 communicating with outside air, and further includes an upper chamber space 52 that is a first chamber and a lower chamber space 53 that is a second chamber. Have. The fuel cell 1 is housed in the upper chamber space 52, that is, in the upper chamber space 52 together with the reforming unit 3 and the evaporation unit 2. The lower chamber space 53 of the housing 5 accommodates a tank 4 for storing liquid-phase water reformed by the reforming unit 3. The tank 4 is provided with a heating unit 40 having a heating function such as an electric heater. The heating unit 40 heats the water stored in the tank 4 and can be formed with an electric heater or the like. When the environmental temperature such as the outside temperature is low, the water in the tank 4 is heated to a predetermined temperature (for example, 5 ° C., 10 ° C., 20 ° C.) or more by the heating unit 40 based on a command from the control unit 100X. Freezing is suppressed. As shown in FIG. 11, the water supply passage 8 having a water sensor 87 and a water supply passage 87 that communicates the outlet port 4p of the tank 4 on the side of the lower chamber space 53 and the inlet port 2i of the evaporator 2 on the side of the upper chamber space 52 is a pipe. It is provided in the housing 5. As shown in FIG. 11, in the housing 5, the tank 4 is disposed on the lower side of the evaporator 2, so that the water supply passage 8 basically extends along the vertical direction. The water supply passage 8 is a passage through which water stored in the tank 4 is supplied from the tank 4 to the evaporation unit 2. The water supply passage 8 is provided with a pump 80 that functions as a water conveyance source for conveying water in the tank 4 to the evaporation unit 2. A control unit 100X for controlling the pump 80 is provided. Further, the control unit 100X controls the pumps 80, 71, 79, 60.

  When the pump 60 is driven at the time of starting the system, the fuel flows from the fuel passage 6 to the combustion portion 105 via the evaporation portion 2, the reforming portion 3, the anode gas passage 73, the anode 10 of the fuel cell 1, and the flow passage 103. . Cathode fluid (air) flows to the combustion section 105 through the cathode gas passage 70, the cathode 11, and the flow path 104 by the cathode pump 71. When the ignition unit 35 ignites in this state, combustion occurs in the combustion unit 105, and the reforming unit 3 and the evaporation unit 2 are heated. When the pump 80 is driven in the positive mode while the reforming unit 3 and the evaporation unit 2 are heated in this way, the water in the tank 4 flows from the outlet port 4p of the tank 4 toward the inlet port 2i of the evaporation unit 2. It is conveyed in the water supply passage 8 and heated by the evaporation unit 2 to be steam. The water vapor moves to the reforming unit 3 together with the fuel supplied from the fuel passage 6 (preferably in a gaseous state, but may be in a liquid phase in some cases). In the reforming unit 3, the fuel is reformed with water vapor to become an anode fluid (hydrogen-containing gas). The anode fluid is supplied to the anode 10 of the fuel cell 1 through the anode gas passage 73. Further, a cathode fluid (oxygen-containing gas, air in the case 5) is supplied to the cathode 11 of the fuel cell 1 through the cathode gas passage 70. Thereby, the fuel cell 1 generates electric power. The anode fluid off-gas discharged from the anode 10 and the cathode fluid off-gas discharged from the cathode 11 pass through the flow paths 103 and 104, reach the combustion section 105, and are combusted in the combustion section 105. The hot exhaust gas is discharged outside the case 5 through the exhaust gas passage 75.

When the pump 80 is driven during the power generation operation of the system, the water in the tank 4 is conveyed from the outlet port 4p of the tank 4 toward the inlet port 2i of the evaporation unit 2 through the water supply passage 8 and heated by the evaporation unit 2 Into steam. The steam moves to the reforming unit 3 together with the source gas supplied from the source gas passage 6. In the reforming unit 3, the fuel is reformed with water vapor to become an anode gas (hydrogen-containing gas). When the fuel is methane-based, the generation of anode gas by steam reforming is considered to be based on the following equation (1). However, the fuel is not limited to methane.
(1) ... CH ₄ + 2H ₂ O → 4H ₂ + CO ₂
CH ₄ + H ₂ O → 3H ₂ + CO
The generated anode gas is supplied to the anode 10 of the fuel cell 1 through the anode gas passage 73. Further, cathode gas (oxygen-containing gas, air in the housing 5) is supplied to the cathode 11 of the fuel cell 1 through the cathode gas passage 70. Thereby, the fuel cell 1 generates electric power. The high-temperature exhaust gas discharged from the fuel cell 1 is discharged outside the housing 5 through the exhaust gas passage 75.

  A heat exchanger 76 having a condensation function is provided in the exhaust gas passage 75. A hot water storage passage 78 and a hot water storage pump 79 connected to the hot water storage tank 77 are provided. The hot water storage passage 78 has an outward path 78a and a return path 78c. The low temperature water in the hot water storage tank 77 is discharged from the discharge port 77p of the hot water storage tank 77 by the drive of the hot water storage pump 79, passes through the forward path 78a, reaches the heat exchanger 76, and is heated by the heat maintenance action of the heat exchanger 76. Is done. The hot water heated by the heat exchanger 76 returns to the hot water storage tank 77 from the return port 77i via the return path 78c. In this way, the water in the hot water storage tank 77 becomes warm water. The water vapor contained in the exhaust gas is condensed in the heat exchanger 76 to become condensed water. Condensed water is supplied to the water purifier 43 by gravity or the like through a condensed water passage 42 extending from the heat exchanger 76. Since the water purifier 43 has a water purifier 43a such as an ion exchange resin, impurities of condensed water are removed. The water from which impurities have been removed moves to the water tank 4 and is stored in the water tank 4. When the pump 80 is driven, the water in the water tank 4 is supplied to the high-temperature evaporation unit 2 through the water supply passage 8, converted into water vapor in the evaporation unit 2, and supplied to the reforming unit 3. It is consumed as a reforming reaction for reforming. The controller 100X controls the first desulfurizer 100 and the second desulfurizer 200 based on the level of the dew point of the raw material gas flowing through the raw material gas passage 6 and the accumulated amount of raw material gas flowing through the raw material gas passage 6 from the reference time. Maintenance information about maintenance related to is notified.

(Other)
The present invention is not limited to only the embodiments and application modes described above and shown in the drawings, and can be implemented with appropriate modifications within a range not departing from the gist. The fuel cell is not limited to a solid oxide fuel cell, and may be a solid polymer electrolyte fuel cell, a phosphoric acid fuel cell, or a molten carbonate fuel cell depending on circumstances. In short, any fuel cell system having a high temperature installation type first desulfurizer and a low temperature installation type second desulfurizer for desulfurizing the raw material gas may be used. The source gas is not particularly limited, and examples thereof include a gas containing a sulfur compound, and examples thereof include city gas, propane gas, biogas, LPG gas, and CNG gas. The first desulfurizer may be a desulfurizer that desulfurizes sulfur compounds by hydrogenation.

  1 is a fuel cell, 10 is an anode, 11 is a cathode, 2A is a reformer, 2 is an evaporation unit, 3 is a reforming unit, 18 is a power generation module, 19 is a heat insulation wall, 60 is a pump (gas carrier source), 70 Is a cathode gas passage, 73 is an anode gas passage, 75 is an exhaust gas passage, 76 is a heat exchanger, 77 is a hot water storage tank, 78 is a hot water storage passage, 79 is a hot water storage pump, 100X is a control unit, 100 is a first desulfurizer, 200 Indicates a second desulfurizer, 6,500 indicates a raw material gas passage, and 510 indicates a dew point meter.

Claims (6)

A fuel cell having an anode to which anode gas is supplied and a cathode to which cathode gas is supplied; a cathode gas passage for supplying cathode gas to the cathode of the fuel cell; and reforming the raw material gas to generate anode gas A reformer, a gas transport source for supplying the source gas to the reformer, and a source gas passage having a first desulfurizer and a second desulfurizer for desulfurizing the source gas; The anode gas passage for supplying the anode gas to the anode of the fuel cell, and a controller.
The first desulfurizer is disposed upstream of the second desulfurizer, is installed in a relatively high temperature first environment, and the second desulfurizer with respect to a relatively high dew point raw material gas. It is a high-temperature installation type desulfurizer with higher desulfurization performance than
The second desulfurizer is installed in a second environment that is relatively cooler than the first environment, and has a high desulfurization performance for a relatively low dew point raw material gas and a relatively high dew point. It is a low-temperature installation type desulfurizer that tends to have a lower desulfurization performance than a raw material gas having a relatively low dew point relative to the raw material gas,
The control unit performs maintenance on the first desulfurizer and the second desulfurizer based on a dew point of the raw material gas flowing through the raw material gas passage and an integrated flow amount of the raw material gas flowing through the raw material gas passage from a reference time. A fuel cell system for informing maintenance information about the fuel cell system.   The control unit according to claim 1, wherein when the dew point of the source gas flowing through the source gas passage is equal to or higher than a specified dew point, the control unit is configured to change the first flow rate based on an integrated circulation amount of the source gas flowing through the source gas passage from the reference time. The fuel cell system which alert | reports the maintenance information about the maintenance regarding 1 desulfurizer and said 2nd desulfurizer.   2. The control unit according to claim 1, wherein when the dew point of the raw material gas flowing through the raw material gas passage is equal to or higher than a specified dew point, maintenance information for exchanging the first desulfurizer is supplied from the reference time as a raw material gas having a temperature lower than the specified dew point. A fuel cell system that gives notification based on an integrated flow rate of source gas flowing in the source gas path.   2. The control unit according to claim 1, wherein when the dew point of the raw material gas flowing through the raw material gas passage is less than a specified dew point, maintenance information for exchanging the second desulfurizer is supplied from the reference time to a raw material gas having a lower than specified dew point. A fuel cell system that gives notification based on an integrated flow rate of source gas flowing in the source gas path.   2. The control unit according to claim 1, wherein when the dew point of the raw material gas flowing through the raw material gas passage changes before and after a predetermined dew point, the control unit includes an integrated circulation amount of the raw material gas less than the predetermined dew point flowing through the raw material gas passage, and the raw material. A fuel cell system that notifies maintenance information about maintenance relating to the first desulfurizer and the second desulfurizer based on a total circulation amount that is a sum of an integrated circulation amount of raw material gases that exceed a specified dew point flowing through a gas passage.   2. The fuel cell system according to claim 1, wherein the first desulfurizer, the second desulfurizer, and the flow meter are arranged in this order from upstream to downstream in the raw material gas passage.

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