JP5938563B2 - HYDROGEN GENERATOR AND CATALYST PACKING METHOD FOR HYDROGEN GENERATOR - Google Patents

Description

  The present invention relates to a fuel cell system including a hydrogen generator.

  A fuel cell system supplies a hydrogen-containing gas and an oxygen-containing gas to a fuel cell stack (hereinafter simply referred to as a “fuel cell”) that is a main body of a power generation unit, and advances an electrochemical reaction between hydrogen and oxygen. It is a system that takes out the chemical energy generated by this as electric energy and generates electricity. In addition, high-efficiency power generation is possible, and heat energy generated during power generation operation can be easily used, so development is being promoted as a distributed power generation system that can achieve high energy use efficiency. ing.

  In general, the infrastructure of hydrogen-containing gas is often not established, and a conventional fuel cell system is provided with a hydrogen generator equipped with a reforming unit that generates reformed gas (hydrogen-containing gas). ing. The hydrogen generator uses water and natural gas supplied from existing infrastructure as the main component, or LPG as a raw material, and is modified at a temperature of 600 ° C to 700 ° C using a Ru catalyst or Ni catalyst. A reformed gas is generated by a quality reaction. In particular, in order to heat the reforming section to a high temperature, the reforming section is provided with a combustion section such as a burner. In addition, the reformed gas obtained by the reforming reaction usually contains carbon monoxide derived from the raw material, and if the concentration is high, the power generation characteristics of the fuel cell are degraded. Therefore, in addition to the reforming unit, the hydrogen generator includes a Cu—Zn-based catalyst that reduces carbon monoxide by advancing a shift reaction between carbon monoxide and water vapor at a temperature of 200 ° C. to 350 ° C. A metamorphic part, a selective oxidation part that selectively oxidizes carbon monoxide at a temperature of 100 ° C. to 200 ° C. to further reduce carbon monoxide, and methane that reduces carbon monoxide by selectively methanation In many cases, a reaction section such as a selective removal section such as a decontamination section is provided. Generally, the reaction part for performing each reaction is composed of a catalyst part filled with a granular catalyst, and each reaction is advanced by passing a raw material.

  During the start-up operation and the stop operation of the hydrogen generator, thermal deformation occurs due to the combustion heat in the hydrogen generator main body. Due to this thermal deformation, thermal deformation also occurs in the catalyst part, and a part of the catalyst in the catalyst part is crushed and the reaction gas flow path in the catalyst part is obstructed, leading to a decrease in the capacity of the hydrogen generator. There was a problem to do. In order to prevent the collapse of the catalyst in the catalyst portion with respect to such a problem, Patent Document 1 discloses that the catalyst is partitioned by a partition member, a plurality of layers are formed in the extending direction, and a granular reforming catalyst caused by thermal deformation A structure of a fuel reformer that reduces the crushing of the fuel has been proposed. In addition, Patent Document 2 discloses a granular reforming catalyst in which, when crushing occurs, a fragment of a collapsed catalyst is deposited on the lower side of the extending direction of the catalyst portion, that is, in the vicinity of the partition member, and a reaction gas flow path is accumulated. In order to solve the problem of clogging by the fragments, a structure has been proposed in which an opening allowing the passage of the catalyst is provided in the partition member to ensure the flow of the reaction gas.

JP-A-8-208202 International Publication No. 2007/040146

In a conventional hydrogen generator provided with a partition member (hereinafter referred to as a first support portion) that supports the weight of the catalyst, when the catalyst is crushed and catalyst debris accumulates in the vicinity of the first support portion, the reaction gas passes through. In order to secure the flow, it is necessary to provide an opening that allows the passage of the catalyst. However, when the opening is provided in the first support part, there is a possibility that the granular catalyst (hereinafter referred to as the first catalyst) arranged on the first support part falls from the opening. When the first catalyst falls from the opening and is deposited on a granular catalyst (hereinafter referred to as a second catalyst) disposed below the first support portion, the second catalyst is divided by the weight of the dropped catalyst. There is a possibility that the weight increases and cracking (crushing) of the particles of the second catalyst easily proceeds.

In order to solve the conventional problem, the hydrogen generator of the first aspect of the present invention includes a reaction vessel containing a granular catalyst, a support opening larger than the catalyst particles, and a catalyst layer formed of the catalyst layer. It is arranged inside the reaction vessel so as to be separated in the direction of gravity, which is the direction in which the catalyst extends, and a support part for supporting the catalyst, and a protrusion opening projecting upward from the edge of the support part opening in the direction of gravity and a projection portion that forms a front Symbol protrusion opening is configured that protrude in the direction of gravity upwardly from said support portion at a greater opening than the particles of the catalyst.

Moreover, the hydrogen generator of the second aspect of the present invention is configured such that a vent smaller than the catalyst particle diameter is formed in the protrusion .

In the hydrogen generator of the third aspect of the present invention, a plurality of the support portions are provided in the reaction vessel so as to be aligned in the extending direction of the catalyst .

Further, in the hydrogen generator of the fourth aspect of the present invention, the support opening provided in the plurality of support portions arranged in the extending direction of the catalyst does not overlap each other when viewed from the direction in which the plurality of support portions are arranged. The arrangement is as follows.

In addition, in order to solve the above-described conventional problems, the method of filling the catalyst of the hydrogen generator according to the present invention includes a reaction vessel containing a granular catalyst, and a support opening that is larger than the catalyst particles. layers are arranged inside the reaction vessel as divided in the gravity direction as the extending direction of the catalyst, a support portion for supporting the catalyst, and protrudes from the edge of the support opening in the direction of gravity above and a projection portion that forms a protrusion opening, front Symbol protrusion opening from said support portion at a greater opening than the particles of the catalyst a hydrogen generator that protrude in the direction of gravity above, the hydrogen generator in a state of being turned upside down in the gravity direction in use, said through support opening and said protrusion opening, the direction from the support portion opening side to the protrusion opening side, having a step of filling the year catalyst The

  In the present invention, the protrusion of the first support that protrudes upward in the direction of gravity suppresses the fall of the first catalyst, thereby reducing the capacity of the hydrogen generating device due to the collapse of the particles of the second catalyst. Can be prevented.

The longitudinal cross-sectional view which shows schematically a part of internal structure of the reformer main body of the hydrogen generator of embodiment of this invention FIG. 1 is a longitudinal sectional view schematically showing the internal structure of the catalyst part of the reformer body of FIG. (A) The figure which shows the cross-sectional view in the II line of FIG. 2, (b) The figure which shows the cross-sectional view in the II-II line of FIG. The figure which shows the longitudinal cross-sectional view in the III-III line of FIG. 3, and the IV-IV line The longitudinal cross-sectional view which shows roughly a part of internal state at the time of catalyst filling of the hydrogen generator of embodiment of this invention

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 shows a cross-sectional view of the main part of a hydrogen generator 100 according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the reforming unit 20 of the hydrogen generator 100 according to the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along lines II and II-II in FIG.

  In FIG. 1, the hydrogen generator 100 of this Embodiment is comprised from the substantially cylindrical reactor, and has the preheating part 23, the reforming part 20, and the carbon monoxide reduction part at least. At this time, the carbon monoxide reduction unit is configured by the transformation unit 25 and the selective oxidation unit 26.

  Here, the preheating part 23 evaporates the water supplied from the water supply path 3, and preheats the mixed gas of a raw material and water vapor | steam. The reforming unit 20 includes a Ru-based reforming catalyst, and advances the reforming reaction between the raw material supplied from the raw material supply path 4 and water vapor. The shift unit 25, which is a carbon monoxide reduction unit, includes a Cu-Zn shift catalyst, and performs a shift reaction of carbon monoxide and water vapor in the hydrogen-containing gas generated in the reforming unit 20 to contain hydrogen. Reduce the gas carbon monoxide concentration. Further, the selective oxidation unit 26 which is a carbon monoxide reduction unit includes a Ru-based selective oxidation catalyst, and the carbon monoxide remaining in the hydrogen-containing gas after passing through the conversion unit 25 is converted from the air supply unit 19. Using the air supplied to the hydrogen-containing gas after passing through the section 25, it is mainly oxidized and removed.

  Further, the hydrogen generator 100 includes a reforming temperature detection unit 21 that detects the concentration (reaction temperature) of the reforming catalyst (or hydrogen-containing gas) in the reforming unit 20, and a shift catalyst (or a raw material and steam) in the shift unit 25. The metamorphic temperature detector 24 for detecting the temperature of the mixed gas) is provided.

  Further, the hydrogen generator 100 includes a combustion unit 2 that serves as a heating unit for supplying reaction heat necessary for the reforming reaction in the reforming unit 20. And the combustion part 2 is comprised with the burner which burns the combustion gas used as heat reduction, and supplies combustion air to the combustion detection part 22 which consists of a flame rod which detects the combustion state of the combustion part 2, and the combustion part 2 A combustion air supply unit 18 including a combustion fan is provided. At this time, the combustion gas burned in the combustion unit 2 is supplied to the combustion unit 2 via a combustion gas supply path (not shown). The flame rod is a device that detects a combustion state by applying a voltage to ions generated when a flame is formed and measuring an ion current value flowing at that time.

  Further, the combustion exhaust gas generated in the combustion unit 2 is supplied to the reforming unit 20 and the preheating unit 23 of the hydrogen generation device 100 through the wall surface of the hydrogen generation device 100 with the combustion unit 2. The combustion exhaust gas is exhausted to the outside of the hydrogen generator 100 from the upper right outlet in FIG.

  In addition, the preheating unit 23 of the hydrogen generator 100 has the same (shared) side wall surface as the derivation unit 12 and the carbon monoxide reduction unit (the selective oxidation unit 26 and the shift unit 25), and the derivation unit 12 from the carbon monoxide reduction unit. It is configured to be able to exchange heat with the hydrogen-containing gas flowing in the gas, the selective oxidation catalyst of the selective oxidation unit 26, and the shift catalyst of the shift unit 25. At this time, in the deriving unit 12, the hydrogen-containing gas derived from the hydrogen generator 100 and the raw material and water having a low temperature supplied to the hydrogen generator 100 are subjected to heat exchange.

In addition, a water supply unit (not shown) is connected to the water supply path 3 of the hydrogen generator 100, and a raw material supply unit (not shown) is connected to the raw material supply path 4. In addition, a booster pump is used for a water supply part and a raw material supply part, and can control the flow volume of the water to supply and the flow volume of a raw material by controlling the electric current pulse, input power, etc. which are input, for example. Further, the raw material supplied from the raw material supply path 4 may be a raw material containing an organic compound composed of at least carbon and hydrogen elements such as hydrocarbons, for example, city gas mainly composed of methane, natural gas, LPG. Etc. In this case, when a city gas gas infrastructure line is used as a raw material supply source, a desulfurization section for removing sulfur compounds as odorous components in the raw material is connected to the gas infrastructure line. In the desulfurization section, for example, a zeolite adsorption remover that adsorbs a sulfur compound, which is an odorous component in city gas, is used.

  Further, the hydrogen generator 100 is provided with a reforming heat insulating unit 30 so as to be in close contact with an outer wall surface outside the reforming unit 20, and the carbon monoxide reducing unit which is the shift unit 25 and the selective oxidation unit 26 is provided with an external unit. A carbon monoxide removing heat insulating portion 31 is provided with a gap between the wall surface and the wall surface. At this time, the modified heat insulation part 30 and the carbon monoxide removal heat insulation part 31 of the first embodiment are formed of a molded heat insulation material formed using, for example, ceramic fiber raw cotton and a binder.

  Further, a transformation heater 27 is provided in close contact with the outer walls of the transformation unit 25 and the selective oxidation unit 26 of the hydrogen generator 100.

  Then, the hydrogen-containing gas generated by the hydrogen generator 100 having the above-described configuration is supplied from the hydrogen-containing gas outlet passage 40 to a fuel cell (not shown) installed outside through the derivation unit 12. Used for power generation of fuel cells.

  Hereinafter, the start-up operation of the hydrogen generator 100, the normal operation and the stop operation will be described focusing on the operation of the hydrogen generator 100.

  First, a startup operation for starting the hydrogen generator 100 from a stopped state and a normal operation will be described.

  First, when starting the hydrogen generator 100 from a stop state, a raw material is supplied to the combustion part 2 by the instruction | command of an operation control part (not shown). And in the combustion part 2, the supplied raw material is ignited and the heating of the hydrogen generator 100 is started. At this time, the transformation heater 27 is energized, and the transformation unit 25 is heated based on the temperature detected by the transformation temperature detection unit 24. In addition, you may perform the heating operation of the conversion part 25 which is a carbon monoxide reduction part prior to the ignition operation of the combustion part 2. FIG.

Next, after starting the heating in the combustion unit 2, the raw material is supplied to the hydrogen generator 100 (the reforming unit 20) through the raw material supply path 4. At the same time, water is supplied from the water supply path 3 to the hydrogen generator 100 to start a reforming reaction between water and the raw material. In the present embodiment, city gas (13A) containing methane as a main component is used as a raw material. At this time, the amount of water supplied from the water supply path 3 is controlled so that water vapor is about 3 moles with respect to 1 mole of carbon atoms in the average molecular formula of the city gas. (Steam / carbon ratio (S / C) is about 3)
As described above, in the hydrogen generator 100, the steam reforming reaction proceeds in the reforming unit 20, the modification reaction proceeds in the modification unit 25, and the selective oxidation reaction of carbon monoxide proceeds in the selective oxidation unit 26.

  Then, the transformation unit 25 and the selective oxidation unit 26 reach an appropriate temperature for the reaction, and after reducing the carbon monoxide concentration to a predetermined concentration (for example, 20 ppm or less on a dry gas basis), the hydrogen-containing gas is passed through the derivation unit 12. For example, supply to a fuel cell or the like is started. Thereby, a normal driving operation is started.

  Hereinafter, the stop operation for stopping the hydrogen generator 100 will be described.

  First, the supply of the raw material and water is stopped, and the temperature of each catalyst in the reforming unit 20, the shift unit 25, and the selective oxidation unit 26 in the hydrogen generator 100 is lowered. At this time, the basic operation of the combustion unit 2 is stopped.

Next, after lowering the temperature of each catalyst to the set temperature, the raw material is circulated through the hydrogen generator 100, and the operation of replacing the hydrogen-containing gas staying inside the gas path with the raw material is performed. Perform the sealing operation.

  Although the hydrogen generator is operated by each of the above-described operations, thermal deformation of each catalyst portion occurs at each start-up operation and stop operation of the hydrogen generator.

  During the start-up operation, the surface temperature of the reformer inner cylinder 50 rises to 700 ° C. or higher. However, the temperature rise of the reforming unit outer cylinder 51 is slower than that of the reforming unit inner cylinder 50, and a large temperature difference occurs between the two. That is, the amount of expansion in the radial direction of the reforming unit inner cylinder 50 is larger than that of the reforming unit outer cylinder 51, and the charged portion of the granular reforming catalyst P, that is, the reforming unit inner cylinder 50 and the reforming unit outer cylinder 51 The width of is narrowed. As a result, compressive stress is applied to the granular reforming catalyst P, and part of the granular reforming catalyst P may be crushed.

  Therefore, the reforming unit 20 of the hydrogen generator of the present embodiment has a configuration as shown in FIG.

Specifically, the granular catalyst P in the reforming unit is supported by the second support member 54, and the intermediate height thereof is supported by the first support member 53. Under each support member, there is a catalyst upper space 60 in the upper part of the catalyst layer, and when a compressive stress is applied to the granular catalyst P, the upper catalyst can freely move in the upper direction. The pressure on the catalyst is reduced.

  At this time, the first support member 53 may have a shape that can support the particles of the first catalyst, and may be, for example, a flat plate. Further, for example, a net shape having a plurality of holes in a flat plate may be used. Similarly to the first support portion, the second support member 54 may have any shape that can support the particles of the second catalyst. For example, the second support member 54 may be a flat plate or a net-like shape having a plurality of holes in the flat plate. Also good. In this embodiment, since the granular catalyst P having a diameter of about 3 mm is used, the size of the hole and the opening of the mesh may be configured to prevent the catalyst from passing therethrough.

  The first support member 53 is welded to the inner surface of the reformer outer cylinder 51 or the outer surface of the reformer inner cylinder 50 at the support member outer edge 53A or the support member inner edge 53B shown in FIG. Fixed. Further, the first support member 53 is provided with a vent hole 53D having a size such that the particulate catalyst P does not pass therethrough, and the reaction gas flow in the reforming unit 20 is ensured. Further, the first support member 53 is provided with an opening 53E that allows passage of the granular catalyst P.

  Further, during the stop operation, the temperature drop of the reformer outer cylinder 51 is slower than the drop in the surface temperature of the reformer inner cylinder 50, and a large temperature difference occurs between them. That is, the amount of contraction in the radial direction of the reforming unit inner cylinder 50 is larger than that of the reforming unit outer cylinder 51, and the charged portion of the granular reforming catalyst P, that is, between the reforming unit inner cylinder 50 and the reforming unit outer cylinder 51. The width expands. Thus, when the granular reforming catalyst P is crushed, the fragments are pushed downstream in the extending direction of the reforming unit 20 and are accumulated in the vicinity of the first support member 53 and the second support member 54. .

Simply, in the configuration in which the first support member 53 is provided with an opening 53E that allows passage of the granular catalyst P, many of the vent holes 53D of the first support member 53 are blocked by fragments of the granular reforming catalyst P. Even if such a situation occurs, the flow path of the reforming reaction gas is secured in the opening 53E. At this time, the first catalyst P1 disposed on the upper side of the first support member 53 is crushed. In this case, the first catalyst P1 sequentially moves to the downstream side through the opening 53E that allows passage of the granular catalyst P on the first support member 53, and accumulates on the second catalyst P2. At this time, since the weight applied to the second catalyst P2 increases by the weight of the first catalyst that has dropped, the cracking (crushing) of the particles of the second catalyst is promoted.

Therefore, in the embodiment of the hydrogen generator of the present invention, as shown in FIG. 4A, a protrusion 61 that protrudes upward with respect to the direction of gravity is provided at the edge of the opening 53E of the first support member 53. . The protrusion 61 formed on the edge of the opening 53E of the first support member 53 suppresses the first catalyst P1 from dropping. As a result, an increase in the weight of the first catalyst P1 deposited on the upper part of the second catalyst P2 is suppressed, and the collapse of the second catalyst P2 and a reduction in the capacity of the hydrogen generator can be prevented.
4B and 4C show a modification of the shape of the protrusion 61. FIG. Note that the protrusion 61 may have a shape that protrudes upward in the direction of gravity, and is not limited to the shape shown in FIG. 4, and may be a first support even if another part is attached by welding or the like. It may be molded integrally with the member 53. Further, the protrusion 61 may be a plate-like member or a net-like member, or a row of rod-like members, and may be configured to prevent the particulate catalyst P from passing therethrough. However, the protrusion opening 63 constituted by the protrusion 61 needs to be opened larger than the size through which the granular catalyst P can pass. The protrusion 61 is preferably provided with a vent 64 that does not allow passage of the catalyst and allows the reaction gas to flow. With this configuration, it is possible to suppress the passage of the catalyst particles and to allow the gas flowing through the reaction vessel to pass through the protrusion. Therefore, the gas flow in the reaction vessel can be made more uniform, and the variation in the reaction location in the reaction vessel can be reduced.

  Furthermore, it is preferable to provide a plurality of first support members in the extending direction of the catalyst so that the height of the catalyst layer is further reduced. This is because by reducing the height of the catalyst layer in the catalyst portion, the weight applied to the catalyst below the catalyst layer can be reduced, and the collapse of the catalyst can be suppressed.

  Moreover, it is preferable to arrange | position the 1st support member opening 53E in the direction which does not overlap seeing from the extending direction of a catalyst. This is because, in the case where a plurality of first support members 53 are provided, the reaction gas that flows through the first support member openings by changing the direction of the first support member openings 53E provided in each support member for each catalyst layer. This is because the flow can be redirected and diffused for each catalyst layer, and a uniform reaction can be obtained.

  On the other hand, in the manufacture of the hydrogen generator 100, the first support member is provided with an opening 53E larger than the granular catalyst P, and the partitioned spaces are in communication with each other. It is possible to fill the space partitioned by the first support member with the granular catalyst P through the support member opening 53E, but the protrusion 61 provided in the first support member opening 53E has catalyst particles in the direction of 62B. Since the passage of the catalyst particles is hindered in the direction of 62A, the catalyst can be filled from the direction of 62B, so that an efficient filling operation can be performed. For this reason, in the catalyst filling process of the hydrogen generator 100, the hydrogen generator 100 is reversed from the installation direction during use to the direction of gravity, and the lower side of the direction of gravity when using the hydrogen generator 100, the direction 62B. Therefore, it is preferable to fill the granular catalyst P.

  FIG. 5 shows a state around the protrusion when the granular catalyst P is filled from the direction 62B. Here, the protrusion opening 63 of the protrusion 71 is preferably smaller than the particle diameter of the granular catalyst P and is ½ or more of the particle diameter of the catalyst. This is because, when filling the catalyst P, the projection opening 63 is lowered, so that the difficult filling area 73 can be reduced and the filling rate of the granular catalyst P can be increased. The height of the protrusion is preferably determined in consideration of the frequency variation distribution of the particle diameter of the granular catalyst P.

  The first catalyst and the second catalyst may be any catalyst that is used in a hydrogen generator and is necessary for the process of generating hydrogen. For example, a reforming catalyst, a shift catalyst, a selective oxidation catalyst, a desulfurization catalyst, or a methanation It may be a catalyst.

  As described above, the hydrogen generator and the catalyst filling method of the hydrogen generator according to the present invention can suppress the fall of the catalyst and prevent the hydrogen generator from being degraded due to the collapse of the catalyst particles below. Therefore, it can be applied to uses such as a fuel cell system equipped with a hydrogen generator.

20 reforming section 50 reforming section inner cylinder 51 reforming section outer cylinder 53 first support member 54 second support member 60 catalyst upper space 61 projecting section 63 projecting section opening 64 vent hole 71 projecting section

Claims (5)

A reaction vessel containing a granular catalyst;
A support part for supporting the catalyst is formed, wherein a support part opening that is larger than the catalyst particles is formed, the catalyst layer is disposed in the reaction vessel so as to be separated in a gravitational direction that is an extension direction of the catalyst. When,
A protrusion that protrudes upward in the direction of gravity from the edge of the support opening to form a protrusion opening ;
Equipped with a,
Before SL protrusion opening is projected in the gravity direction upward from the supporting portion at a greater opening than the particles of the catalyst,
Hydrogen generator. The projections, the smaller vent than the particle size of the catalyst is formed, the hydrogen generating apparatus according to claim 1. The hydrogen generator according to claim 1 or 2, wherein a plurality of the support portions are provided inside the reaction vessel so as to be aligned in the extending direction of the catalyst . Said support aperture between which is provided a plurality of the supporting portions arranged in the extending direction of the catalyst is disposed so as not to overlap when viewed from a direction of arrangement of a plurality of the support portions, hydrogen according to claim 3 Generator. A method for filling a catalyst in a hydrogen generator comprising a reaction vessel containing a granular catalyst ,
The hydrogen generator has a support opening that is larger than the catalyst particles, and the catalyst layer is disposed inside the reaction vessel so as to be separated in a gravitational direction that is an extension direction of the catalyst. A support part for supporting, and a protrusion part protruding from the edge of the support part opening upward in the direction of gravity to form a protrusion part opening ,
Before SL protrusion opening is projected in the gravity direction upward from the supporting portion at a greater opening than the particles of the catalyst,
The catalyst is charged from the support opening side to the protrusion opening side through the support opening and the protrusion opening in a state where the gravity direction when the hydrogen generator is used is inverted. A catalyst filling method of a hydrogen generator comprising the steps.