JP5762318B2 - Continuous fixed bed catalytic reactor and catalytic reaction method using the same - Google Patents

Description

  The present invention relates to a reaction apparatus for performing a chemical reaction of a fluid using a bulk catalyst and a technique of a catalytic reaction method using the reaction apparatus.

  In a fluid chemical reaction using a fixed bed catalytic reactor filled with a catalyst, there is often a problem of producing a solid product and locally blocking the catalytic reactor.

  For example, Patent Document 1 discloses a technique for reforming tar gas by bringing hydrogen, carbon dioxide, water vapor, and tar-containing gas into contact with a catalyst containing nickel, cerium, and aluminum in a fixed bed catalytic reactor. In this technique, it is described that solid carbon is deposited on the surface of the catalyst during reforming, and in order to remove it, it is necessary to perform a regeneration treatment in which water vapor or air is brought into contact with the carbon.

  Patent Document 1 (Japanese Patent Laid-Open No. 2010-77219) also exemplifies the use of moving bed type and fluidized bed type catalytic reactors. In these methods, carbon deposited on the catalyst surface is removed during the reaction operation. Yes. However, such reactors are more complicated than fixed bed catalytic reactors, and in the case of fluidized bed type, the operation tends to become unstable. It is not common as a reactor for treating fluids.

  On the other hand, in a fixed bed reactor using a bulk catalyst, which does not have the above-mentioned problems in moving bed type and fluidized bed type catalyst reactors, usually a catalyst layer, which is a stack of bulk catalysts randomly, is sandwiched. Spaces are provided on both sides, and a fluid is circulated from one space to the other for reaction. In order to form a space on both sides of the catalyst layer, a holding mechanism for preventing the catalyst from falling is necessary. A typical example of the catalyst holding mechanism is described in Patent Document 2 (Japanese Patent Laid-Open No. 2011-6289). ing. Here, the holding of the catalyst and the ventilation of the raw material gas and the reformed gas are ensured by using a punching metal plate or a net having a hole diameter sufficiently smaller than the catalyst diameter. FIG. 1 shows an example of a schematic diagram in which the structure of the main part is simplified. A catalyst layer 2 in which catalysts are randomly stacked is accommodated in a catalyst reaction vessel 1, and the catalyst is held below the catalyst layer. This is done by a punching metal plate or net 3 provided on the surface. In FIG. 1, the raw material gas 4 flows in from the inlet 5 and flows out as the reformed gas 7 from the outlet 6.

JP 2010-77219 A JP 2011-6289 A

  However, the prior art has the following problems. For one thing, punching metal and nets cannot set the aperture ratio (1- [total opening area] / [apparent cross-sectional area of the flow path]) large due to restrictions on the strength of the holding mechanism (maximum of about 70). %), There is a problem that high ventilation resistance and blockage are likely to occur. That is, for example, in the case of a holding mechanism using a net, since there is an upper limit of mesh opening, in order to increase the aperture ratio, the wire diameter of the wire constituting the net must be reduced. However, under the relatively high temperature operating conditions required for catalytic reactions, extremely thin wires cannot be employed because they are easily broken by contact with a reactive gas that can be contained in the raw material gas. Another problem is that the openings are isolated for each hole (the entire circumference of the small opening is surrounded by a solid). For example, in the case of a reforming reaction of a raw material gas containing tar using a catalyst, Solids such as carbon generated on the catalyst surface accompanying the reforming reaction fall and scatter on the holding mechanism, adhere to the outer periphery of each opening of the holding mechanism, and gradually grow toward the center of the opening. There is a problem that the opening is blocked and ventilation becomes impossible. In particular, in order to maintain a high temperature or highly corrosive fluid, it is necessary to use Ni-containing alloys (stainless steel, Inconel, Hastelloy, etc.) for strength and corrosion resistance. Although desirable, metal Ni often acts as a reforming catalyst for hydrocarbons, depositing solids such as carbon on the surface of the catalyst cage, and this effect also helps to close the opening.

  Accordingly, the present invention provides a catalytic reaction apparatus that realizes a high opening ratio and prevention of clogging in a catalyst cage, and a catalytic reaction method that reforms tar-containing gas with high efficiency using the catalytic reaction apparatus. The purpose is to provide.

  In order to solve the above-mentioned problems, the following solutions have been invented as a result of the inventor's research.

(1) An inflow path for a raw material fluid for catalytic reaction and an outflow path for a reforming fluid;
A catalytic reaction vessel connected to the inflow and outflow paths and containing the bulk catalyst;
A catalyst having a structure in which a bulk catalyst is held by tip portions of a plurality of pins in at least one of connection portions between an inflow path and an outflow path of a catalyst reaction vessel, and a catalytic reaction fluid can flow through a space between the pins. A continuous fixed-bed catalytic reactor characterized by comprising a holding means.

(2) The plurality of pins are arranged substantially in parallel, and for all of the pins, the interval between adjacent pins is:
[Pin axis distance]-[Pin outer diameter dimension] <[Minimum mesh opening dimension through which catalyst can pass]
The continuous fixed bed catalytic reactor according to (1), characterized in that:

  (3) The continuous fixed bed catalytic reactor according to (1) or (2), wherein the curvature of the pin in contact with the catalyst is smaller than the maximum curvature of the outer surface of the catalyst.

  (4) The continuous catalytic reactor according to any one of (1) to (3), wherein the raw material fluid is a gas, and a product of the catalytic reaction includes a solid or a liquid.

  (5) The continuous fixed bed catalytic reactor according to (4), wherein a space for storing the solid or liquid product is provided below a contact portion of the pin with the catalyst.

  (6) The continuous type according to (4) or (5), wherein the raw material fluid is a gas containing a hydrocarbon, and the product of the catalytic reaction is a gas and a solid or a liquid. Catalytic reactor.

  (7) The continuous fixed bed catalytic reaction according to (6), wherein the raw material fluid is a gas containing tar, and the product of the catalytic reaction contains solid hydrocarbon or solid carbon. apparatus.

(8) The catalyst is a composite oxide containing nickel, magnesium, cerium, and aluminum, and is made of a composite oxide not containing alumina, and the composite oxide comprises NiMgO, MgAl ₂ O ₄ , CeO. The continuous fixed bed catalytic reactor according to (7), comprising _two crystal phases.

(9) The catalyst is a catalyst made of a composite oxide containing nickel, magnesium, cerium, zirconium, and aluminum, and the composite oxide contains NiMgO, MgAl ₂ O ₄ , Ce _x Zr _1-x O ₂ (0 <x <1) The continuous fixed bed catalytic reactor according to (7), comprising a crystalline phase.

(10) The catalyst is
A tar-containing gas reforming catalyst which is a composite oxide represented by aM · bNi · cMg · dO,
a, b, and c satisfy a + b + c = 1, 0.02 ≦ a ≦ 0.98, 0.01 ≦ b ≦ 0.97, and 0.01 ≦ c ≦ 0.97,
d is a value at which oxygen and positive elements are electrically neutral;
M is Ti, Zr, Ca, W, Mn, Zn, Sr, Ba, Ta, Co, Mo, Re, platinum, runium, palladium, rhodium, Li, Na, K, Fe, Cu, Cr, La, Pr. , Nd, and at least one element selected from Nd,
At least one oxide selected from silica, alumina, and zeolite is added to the composite oxide, and the content of the oxide selected from silica, alumina, and zeolite is 1 to 90% by mass with respect to the composite oxide. % Of the continuous fixed-bed catalytic reactor according to (7).

  (11) A continuous fixed bed catalytic reaction method, wherein the catalytic reaction is carried out using the continuous fixed bed catalyst reaction apparatus according to any one of (1) to (10).

  According to the present invention, there is provided a catalytic reactor in which both a high opening ratio and prevention of clogging in a catalyst holder are realized. Further, since the ventilation resistance of the catalyst cage can be reduced, it is possible to vent the catalyst layer with less blower power. Further, the tar-containing gas can be reformed with high efficiency using the catalytic reaction apparatus.

It is a schematic cross section of the catalyst reaction apparatus of a prior art. It is a schematic diagram of the catalytic reaction apparatus of the 1st Embodiment of this invention. It is a schematic diagram of the catalyst holder | retainer in the 1st Embodiment of this invention. It is another schematic diagram of the catalyst holder in the first embodiment of the present invention. 3 shows another form of catalyst retainer. It is a schematic diagram of the catalytic reaction apparatus of the 2nd Embodiment of this invention. It is a schematic diagram of the catalytic reaction apparatus of the 3rd Embodiment of this invention. It is a schematic diagram of the other catalytic reaction apparatus of the 3rd Embodiment of this invention.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[First embodiment]
(Overall structure)
FIG. 2 shows an example of a catalytic reaction apparatus as a three-view diagram of a front view, a plan view, and a side view on the left side, and an enlarged view of a BB cross section on the right side.

  Although not limited, the catalyst reaction vessel 11 has a rectangular cross section in a horizontal plane, accommodates a catalyst layer 12 in which a massive catalyst is randomly stacked, and houses an inflow pipe 13 of a reaction fluid 16 via an inlet 13a in the lower part. Moreover, the upper portion is connected to the outflow pipe 14 of the reformed fluid 17 through the outlet 14a. 15 is a lid | cover of a catalyst reaction container for taking in / out a catalyst offline. The catalyst reaction vessel 11 has a catalyst holder 18 at the lower inlet 13a as seen in the BB cross section. Although not shown, the catalyst reaction device may be arranged in a heating furnace to give the temperature and heat necessary for the catalyst reaction.

  The catalyst holder 18 is a structure in which a large number of pins 19 as shown in FIG. 3 are held by a bottom plate 20 at the bottom of the pins, and a catalyst holding means for holding the massive catalyst 12 at the tip of the pins 19. It is. By setting the gap interval between the pins 19 to be smaller than the size of the massive catalyst 12, the massive catalyst 12 can be held at the tip portions of these pins 19, and the gap between the pins allows the flow of the raw material fluid to flow. It functions as an inlet or outlet for reforming fluid.

In this catalyst holder 18, the pins 19 have the same shape, but need not necessarily have the same shape. It is only necessary to hold the massive catalyst at the tip of the pin and allow fluid to flow through the gap between the pins, and the size, length, and angle of the pins need not be the same, and the pins are not limited to a straight line.
In this catalyst holder 18, the tip of the pin 19 forms the same plane, but the surface formed by the tip of the pin 19 is a curved surface, or exceptionally from the surface where some pins form the tip. It may stick out.
According to such a catalyst holder 18, a high opening ratio and prevention of clogging are realized.

(Catalyst cage pin arrangement)
Referring to FIG. 4, the arrangement of the pins 19 of the catalyst retainer shown in FIG. 3 is viewed from the front end side of the pin (a plane perpendicular to the axis of the pin), and an enlarged view of a part thereof. The triangle composed of the centers of the three adjacent pins (α, β, γ in FIG. 3) with the center of the pin on the plane perpendicular to the axis of A triangular shape is preferred. As a result, a catalyst holding structure can be realized with a minimum number of pins for the required cross-sectional area of the catalyst to be held.

  All the pins are preferably arranged so that the central axes of the pins are parallel to each other. This is because the opening on the side surface of the pin becomes uniform and becomes more difficult to close. In a region where the pin shafts are extremely close to each other, blockage between the pin side surfaces is likely to occur. The length of the portion where the pins are parallel is determined so as to form a space in which the raw material fluid and the reformed fluid can freely flow without closing the gap between the pins.

When there is a design convenience, the distance between the central axes gradually increases or decreases toward the catalyst direction and does not necessarily have to be parallel. Similarly, although the central axes of the pins are parallel, the interval between the pins may be set so as to gradually widen or narrow.
The length of the portion where the pins are substantially parallel is determined so as to form a space in which the reaction fluid can freely flow without closing the gap between the pins.

(Spacing between pins)
The pins are preferably arranged as shown in FIG. 3, but in this case, it is desirable that the distance between the pins satisfies the following inequality.
[Pin-axis distance]-[Pin outer diameter] <[Minimum mesh opening size through which catalyst can pass]
[Outer Diameter of Pin]: The outer diameter of the pin is the sum of the radii between the axes of the two pins (the distance from the axis of the pin to the outer diameter), which is the diameter of the pin in the preferred arrangement of cylindrical pins.
"Mesh": A sieve eye.
“Aperture size”: Based on the general definition of JIS, etc., assuming a square opening, but in the present invention, the smallest of the representative dimensions (diameter, height, etc.) of a single catalyst mass outer shape Corresponds to

That is, if the distance between the shafts excluding the diameters (outer diameters) of all the pins is smaller than the minimum mesh opening size through which the catalyst can pass, particularly at the top part (pin tip part) of the catalyst cage, the catalyst mass The child does not fall between the pins and can be supported by these pins. Some catalyst dimensions are exceptionally smaller than the distance between the axes excluding the pin diameter, such as a small piece of catalyst caused by catalyst failure, but may fall between the pins. By providing sufficient storage space for falling objects below and below 18, there is no particular problem at least from the viewpoint of clogging the catalytic reaction vessel.
From the viewpoint of air permeability and resistance to blockage of the cage, the opening ratio (1- [total pin cross-sectional area] / [apparent cross-sectional area of the channel]) in the vertical cross section in the main flow direction of the air flow is 90% or more. It is preferable. The upper limit of the aperture ratio is restricted by the cross-sectional area of each pin determined from the buckling resistance of the pin.

(Characteristics of the first invention)
By using such a catalyst holder, the strength can be maintained even if the aperture ratio is increased unlike the case of punching metal or mesh, so that the substantial aperture ratio (in the contact portion of the pin row to the catalyst) The ratio of the space in the plane perpendicular to the pin axis can be set to a high value of 90% or more, which cannot be realized by the conventional technology. More than 95% is possible.

  Further, the pins 19 of the catalyst holder 18 are all isolated within the vertical cross section of the pin central axis, and the spaces extending between the pin rows are connected to each other. However, it is not easy for this solid to bridge between adjacent pins to close the opening.

(Pin shape)
A round bar (cylindrical shape) is preferable because the surface is smooth and the catalyst is hardly damaged. It may be prismatic or other shapes for reasons of manufacturing convenience. From the viewpoint of preventing buckling, the central axis is preferably a straight line. It may be a bent bar for manufacturing or design reasons.

(Pin shape at the contact portion of the pin with the catalyst: feature of the second invention)
It is desirable that the pin shape in the contact portion of the pin with the catalyst, that is, the shape of the tip of the pin is substantially a shape that suppresses catalyst breakage at the time of contact with the catalyst.

The tip of the pin may be flat. In the case of a spherical catalyst lump, when the holding surface in the catalyst holding mechanism is a flat plate, the contact area becomes maximum (that is, the surface pressure is minimum), so that the catalyst is hardly damaged (actually contacts the concave surface). In some cases, the contact area becomes larger, but when a large number of catalyst masses simultaneously contact the holding surface, a shape in which a concave surface is provided everywhere cannot be realized). When the flat part of the tip of the pin, which is the holding surface, is in contact with the catalyst mass, if the flat part is sufficiently wide (for example, 0.1 mm ² or more), the contact pressure at that time is the case where the catalyst is in contact with the flat plate Therefore, the catalyst can be hardly damaged. In the case where the tip of the pin is a flat surface, the surface pressure when the flat portion of the pin and the connecting portion between the side surfaces of the pin are chamfered and the catalyst comes into contact with this portion can be reduced.

Further, the tip of the pin can be a hemisphere having the same diameter as the pin. In the case of a cylindrical catalyst lump, there is an extremely large curvature (corner) at the connection between the bottom and side surfaces of the cylinder, and in this shape of catalyst, chipping of the corner may cause the greatest damage to the catalyst. Therefore, catalyst damage can be prevented by using a hemispherical shape. further,
[Maximum curvature of catalyst mass] >> [Curve of pin tip]
If so, the contact surface pressure of the catalyst is not much different from that when the catalyst is in contact with a flat surface, and the catalyst can be hardly damaged.

(Pin dimensions)
The pin thickness is preferably less than [minimum mesh opening size through which the catalyst can pass] from the viewpoint of securing the aperture ratio. 1/3 or less of the [minimum mesh opening size through which the catalyst can pass] is more preferable. When the catalyst has a ring shape, a cylindrical shape or the like, the diameter is larger than the catalyst hole diameter.

  The length of the pin is preferably [apparent cross-sectional area of fluid flow at the inlet (outlet)] ≧ [apparent cross-sectional area of fluid in the catalyst layer]. When the thickness and width (diameter) of the catalytic reaction vessel are given, the apparent flow cross-sectional area of the fluid at the inlet (outlet) can be adjusted by changing the height of the pin. However, this is not the case when the apparent cross-sectional area of the fluid in the catalyst layer is extremely large (the reaction vessel is flat in the main flow direction, etc.). Here, the “fluid apparent sectional area of the fluid” is an area of a region surrounded by the side wall of the catalyst reaction vessel on a plane perpendicular to the main flow of the raw material fluid or the reforming fluid.

  The aspect ratio (length / thickness) of the pin is preferably 100 or less and more preferably 20 or less from the viewpoint of preventing buckling. However, when the maximum load applied to the pin is sufficiently small, a value larger than this may be used. Further, in order to set the apparent flow sectional area of the fluid at the inlet (outlet) sufficiently large, the pin aspect ratio is preferably 1 or more, and more preferably 5 or more.

(Pin material)
Any material can be used as long as it has strength to retain the catalyst, heat and corrosion resistance to the fluid in contact with it, and contamination resistance to the reaction product. For example, carbon steel, stainless steel, Ni alloy, copper, copper alloy, aluminum, aluminum alloy, titanium, titanium alloy and other metal materials, silica, alumina, silicon nitride, silicon carbide and other ceramics, soda glass, fused quartz, etc. It is glass. Since the catalytic reactor for tar reforming is usually operated at a high temperature of 800 ° C. or higher, Ni alloys such as stainless steel and Hastelloy Inconel are particularly preferable.

(Pin fixing method)
There is no particular limitation, and for example, a catalyst retainer substrate that fixes all pins by welding may be provided.

(Pin placement)
The arrangement of the pins in the catalyst holder of the present invention is preferably parallel as shown in FIG. 3, but the effects of the present invention can be obtained even if they are not necessarily parallel or have different pin spacings. be able to. For example, as described above, the pins may be bent uniformly or each other (in the latter case, the pins are not parallel), or the direction and angle of inclination of the pins rising from the bottom plate are the same. The effect of the present invention can still be obtained.

  For example, as shown in FIG. 5, the catalyst holder 18 may have a shape in which the pins 19 are planted radially. In FIG. 5, 11 is a catalyst reaction device, 12 is a catalyst layer, the pin holding member is not plate-shaped, and the installation position of the pin holding member is also different from FIG.

(Catalytic reaction vessel shape)
Any shape can be applied as long as it has openings at both ends and can accommodate the catalyst between the openings (that is, a cylindrical shape). For example, a cylindrical shape and a rectangular duct shape can be mentioned. Hereinafter, description will be made on the premise of a rectangular duct-like container shape.

  The central axis of the container is defined as the centroid of the horizontal section of the container connected in the vertical direction. When the container is a cylinder, the “width” and “thickness” of the container may be replaced with “diameter” in the following description.

(Catalytic reaction vessel material)
Any material can be used as long as it has strength to retain the catalyst, heat and corrosion resistance to the fluid in contact with it, and contamination resistance to the reaction product. For example, carbon steel, stainless steel, Ni alloy, copper, copper alloy, aluminum, aluminum alloy, titanium, titanium alloy and other metal materials, silica, alumina, silicon nitride, silicon carbide and other ceramics (those processed into bricks) Glass) such as soda glass and fused quartz.

(Catalyst reaction vessel dimensions)
When there is no heat generation / heat absorption due to the catalytic reaction, or when a heat source, a cooling device, and a heat exchange device are separately provided inside the catalytic reaction vessel, there is no particular upper limit on the dimension in the vertical direction of the fluid main flow.

  When there is heat generation and heat absorption due to the catalytic reaction and there is no heat exchange device or the like inside the catalytic reaction vessel, heat must be transferred on the surface of the catalytic reaction vessel and transferred to the inside of the catalytic reaction vessel. For this reason, there is an upper limit for the dimension in the vertical direction of the main fluid flow. The upper limit value may be determined from an engineering point of view by reaction heat, flow rate, heat transfer characteristics, and the like.

  Of course, the fluid mainstream vertical dimension of the catalytic reactor must be larger than the diameter of the catalyst mass. The dimensions in the main flow direction of the catalyst reaction vessel are not particularly limited as long as they are longer than the required length in the main flow direction of the catalyst layer.

(Catalyst block dimensions)
The catalyst mass used in the present invention must satisfy the dimensional constraints on the pin. For example, the catalyst of the following Example 1 can be used.
(Example 1) When a spherical catalyst lump having a diameter of 10 mm is placed in a cylindrical catalyst reaction vessel having an apparent cross section of 100 mm in diameter, a pin height of 100 mm is sufficient. On the other hand, since the pin diameter can be set to 5 mm, the aspect ratio of the pin at this time is about 20, which is feasible.

On the other hand, since the dimensional constraints on the pin cannot be satisfied, the catalyst of Example 2 below cannot be used.
(Example 2) When a spherical catalyst lump having a diameter of 0.1 mm is placed in a cylindrical catalyst reaction vessel having an apparent cross section of 100 mm in diameter, the pin height needs to be at least several tens of mm. On the other hand, the pin diameter must be smaller than the catalyst mass diameter. Therefore, the pin aspect ratio exceeds 100, which is not feasible.

  The size of the catalyst is determined from the efficiency of the catalytic reaction and is not general. The distance between the pins of the catalyst holder may be determined in consideration of the size of the catalyst. However, if necessary, the dimension of the catalyst can be determined in consideration of the distance between the pins of the catalyst holder of the present invention. .

(Catalyst lump shape)
As described above, when a catalyst is held by a specific catalyst holder, a minimum value exists in the smallest representative dimension of the same catalyst outer surface. When the volume of the catalyst reaction vessel is constant, generally, the greater the number of catalysts, the greater the total surface area of the catalyst, and the reaction rate of the reactor can be improved. Accordingly, a sphere or a shape close to a sphere is preferable because the number of catalysts can be easily increased in a certain volume. Moreover, even if the volume enclosed by the outer periphery of a catalyst is the same, the shape with a large surface area of a catalyst lump, for example, a cylindrical shape or a ring shape, is also preferable.

On the other hand, a shape such as a disk that has an extremely small representative length only in one direction is generally unfavorable because it is difficult to hold in the present invention (comparison: conventional meshes and punching metals are less than mesh sizes). The slightly larger disk was the shape that could increase the number of catalysts most). Further, the rod-like shape is not preferable because it is difficult to hold as in the prior art.
The outer dimension of the catalyst mass is preferably about 5 to 50 mm from the viewpoint of easy retention in the catalyst cage and securing a high specific surface area for reactivity.

(Catalyst material and action)
The material and catalytic action of the catalyst to which the catalytic reaction apparatus of the present invention can be applied are not particularly limited as long as it is a catalyst used for a catalytic reaction using a fluid, particularly a gas as a raw material. The catalytic reaction in which the fluid is a gas and the product of the catalytic reaction is a solid or liquid, in particular, the catalytic reaction fluid is a gas containing hydrocarbons, and the product of the catalytic reaction is a gas (and solid or liquid) It can be suitably used for a catalyst used in a catalytic reaction, in particular, a catalyst reaction fluid is a gas containing tar, and a product obtained by the catalytic reaction includes a solid hydrocarbon or solid carbon.

  In general, it can be widely used for oxide catalysts used in the catalytic reaction as described above. In particular, the catalytic reaction fluid is a gas containing tar, and the product of the catalytic reaction is solid hydrocarbon or solid carbon. It can apply suitably for the oxide catalyst used for the catalytic reaction containing.

Specific examples of the catalyst that can be suitably used in the catalytic reactor of the present invention include, for example, oxides containing nickel, magnesium, cerium, and aluminum, including at least one complex oxide, and as a single compound Mention may be made of catalysts for reforming tar-containing gases not containing alumina (WO 2010/134326). A preferred example of this composite oxide is a crystal phase of NiMgO, MgAl ₂ O ₄ , and CeO ₂ , and among the crystal phases, the (200) plane of the NiMgO crystal phase determined by X-ray diffraction measurement is used. The crystallite size is 1 nm to 50 nm, the crystallite size of the (311) plane of the MgAl ₂ O ₄ crystal phase is 1 nm to 50 nm, and the crystallite size of the (111) plane of the CeO ₂ crystal phase is 1 nm to 50 nm. This catalyst contains a large amount of hydrogen sulfide generated when a carbonaceous raw material is thermally decomposed, and even if it is a condensed polycyclic aromatic-based tar-containing gas that easily causes carbon deposition, the accompanying heavy hydrocarbon such as tar Is converted to light hydrocarbons mainly composed of hydrogen, carbon monoxide, and methane, and when the catalyst performance deteriorates, at least one of water vapor and air is converted to the catalyst at a high temperature. By contacting, the carbon is removed from the catalyst and adsorbed sulfur, and the catalyst performance is restored to enable stable operation over a long period of time.

In addition, a reforming catalyst for a tar-containing gas, which is composed of a composite oxide containing nickel, magnesium, cerium, zirconium and aluminum, can be cited (Japanese Patent Application No. 2010-082576). Suitable examples of the composite oxide, NiMgO, include _{MgAl 2 O 4, Ce x Zr} 1-x O 2 (0 <X <1) crystal phase, and further, among the crystalline phase, X-rays diffraction the crystallite size of (220) plane of NiMgO crystalline phase determined by measurement 1 nm to 50 nm, a crystallite size of (311) plane of the MgAl ₂ O ₄ crystalline phase _{1nm~50nm, Ce x Zr 1-x} O 2 crystals The crystallite size of the (111) plane of the phase is preferably 1 nm to 50 nm. According to this catalyst, the tar-containing gas generated when coal or biomass is pyrolyzed can be stably converted into light chemical substances such as carbon monoxide and hydrogen. In particular, even if the tar-containing gas contains a high concentration of hydrogen sulfide in the tar-containing gas, it is brought into contact with the catalyst without desulfurization to reform the tar in the crude gas, or a refined gas The tar-containing gas can be stably converted into light chemical substances such as carbon monoxide and hydrogen by reforming the hydrocarbon component therein.

  Furthermore, a catalyst for reforming a tar-containing gas that is a composite oxide represented by aM · bNi · cMg · dO, wherein a, b, and c are a + b + c = 1, 0.02 ≦ a ≦ 0. .98, 0.01 ≦ b ≦ 0.97 and 0.01 ≦ c ≦ 0.97, d is a value at which oxygen and a positive element are electrically neutral, and M is Li And a reforming catalyst for tar-containing gas which is at least one element selected from Na and K (Japanese Patent Application Nos. 2010-081867, 2010-08197, and 2010-083527). A suitable example of this composite oxide is formed by adding at least one oxide selected from silica, alumina, and zeolite, and further contains at least one oxide selected from silica, alumina, and zeolite. It is preferable that it is 1-90 mass% with respect to the whole complex oxide. According to this catalyst, the tar-containing gas generated when coal or biomass is pyrolyzed can be stably converted into light chemical substances such as carbon monoxide and hydrogen. In particular, even if the tar-containing gas contains a high concentration of hydrogen sulfide in the tar-containing gas, it is brought into contact with the catalyst as it is without desulfurization treatment to reform the tar in the crude gas or in the purified gas. Thus, the tar-containing gas can be stably converted to light chemical substances such as carbon monoxide and hydrogen.

(Effect of limiting catalyst species to tar reforming catalyst)
Conventionally, the cause of the clogging of the catalyst cage has not been clarified. In general, the catalyst retainer is often provided at the most upstream part of the catalyst layer (the lower part of the catalyst layer is retained by the catalyst retainer, and the raw material gas is supplied from below. This layout is preferred because it can avoid the flow of dust into the catalyst layer.) Even if this catalyst retainer is blocked, the cause is due to dust such as coal dust flying from the upstream, or It has been vaguely thought that the mist-like tar generated upstream adheres to the catalyst cage, where it is denatured into a high melting point hydrocarbon and clogged. That is, it has been considered that the cause of the clogging of the catalyst cage is not in the catalyst but in the raw material gas itself.

  However, as a result of detailed investigations of products in the tar reforming reaction using the catalyst layer, which is a series of catalyst species, the present inventors have found that about 70% or more of amorphous carbon (solid carbon) and coke. It was found to be a mixture of solid hydrocarbons such as Generally, amorphous carbon is hardly contained in the dust in the raw material gas. Further, under the temperature condition of less than 900 ° C. as in the above-described reforming reaction test, the mist tar is hardly denatured into amorphous carbon without contacting the catalyst. Therefore, the conventional theory is incorrect, and it has been found that the cause of the clogging of the catalyst cage is due to the catalytic reaction. As a result of further investigation of the physical properties of the solid mixture, it was found that the catalyst of these materials had relatively low adhesion to the catalyst surface. In addition, tar reforming performance using these catalysts is extremely high in tar reforming performance, so that the amount of coking generated with the reforming reaction is extremely large compared to reforming reactions by other methods. For this reason, in the tar reforming reaction using these catalysts, at least a part of the solid mixture is separated from the catalyst surface and is captured by the catalyst holder or the like by the action of gravity or air flow. In the conventional tar reforming reaction, it was found that the use of a conventional catalyst cage could easily cause clogging.

  The present invention achieves a high aperture ratio and interconnected aperture shapes, and is applied to this type of catalytic reaction, thereby leading to the passage of a solid product that can be detached from the catalyst surface and captured in the catalyst cage during the reaction. There is a remarkable effect that the adverse effect of can be reduced.

(Other applicable examples)
The present invention can be suitably used for the following catalytic reaction apparatus that causes coking, in addition to the catalytic reaction apparatus and catalyst exemplified above.
1) Methane reforming catalytic reactor: “Comparative Example” of JP-A-2006-35172 describes that a large amount of coking (carbon deposition) occurs using methane gas, which is a hydrocarbon, as a raw material gas.

2) City gas reforming catalytic reactor: Patent Document 2 describes a case of coking.
3) In addition, catalytic reactors for reforming various petroleum refined gases such as LPG and natural gas, and fuel cells that generate hydrogen by generating gas by acting hydrogen-containing gas and oxidant gas. The present invention can be applied to a catalytic reaction apparatus (eg, JP-A-2009-48797).

[Second Embodiment]
The catalyst reaction apparatus of the present invention is not limited to the example of FIG. 3, but may be a catalyst holder / catalyst layer arrangement as shown in FIG.

  In this example, the reference numerals indicate the same members as in FIG. 3, but the inflow pipe 13 for the raw material gas 16 and the outflow pipe 14 for the reformed gas 17 are on both sides of the upper part of the catalytic reaction container 11 with respect to the catalytic reaction container 11. The catalyst holder 18 is disposed on both sides of the catalyst reaction vessel 11 so as to hold the catalyst from the side. The structure of the catalyst holder 18 itself can be the same as shown in FIG. 3 or described above. The raw material gas 16 flows from the inflow pipe 13 into the catalyst 12 held by the catalyst holder 18, using a channel between the pins of the catalyst holder 18 (left side). The reformed gas generated by reacting with the catalyst 12 in the catalyst reaction vessel 11 enters the outflow pipe 14 using the space between the pins 18 of the catalyst holder 18 (right side) holding the catalyst 12 as a flow path, and enters the outside. It is taken out.

[Third Embodiment: Space for Retaining Solid or Liquid Product]
Part of the solid or liquid product produced by the catalytic reaction is separated from the catalyst surface and transported to the downstream side of the drop or main stream, and is deposited between the pins of the catalyst cage provided at these sites. May interfere with ventilation. Therefore, a storage space for supplementing the solid or liquid product separated from the catalyst surface can be provided in the lower part of the catalyst reaction vessel or in the downstream part of the main stream.

  An example of the storage space is shown in FIG. FIG. 7 is a cross-sectional view of the front of the catalytic reaction device, as well as a cross-sectional view along AA and a cross-section along BB. The basic structure of the catalytic reaction apparatus is the same as that shown in FIG. 2, but in this example, the inflow pipe and the outflow pipe are installed above and below (top and bottom surfaces) of the catalytic reaction vessel 11 (inlet 13a). And the outlet 14a is indicated by a broken line). In the lower (bottom) catalyst reaction vessel 11, for example, the catalyst holder 18 is installed in a circular pipe 22 larger than the catalyst holder 18, and reaction by-products that have fallen into the catalyst holder 18 are removed from the catalyst holder 18. It can be dropped from the side into the space 23 below, and the space below the catalyst holder 18 formed by the circular tube 22 can be used as the storage space 23. In FIG. 6, 25 is a fallen object, and the circular pipe 22 is used as a part of the inflow pipe. The member that forms the storage space is not limited to a circular pipe.

  At this time, as shown in FIG. 8, a louver 24 may be further provided on the upper portion of the reservoir 23 to prevent re-scattering of the supplemented product.

[Catalytic reaction method]
In the catalytic reaction apparatus and catalytic reaction method of the present invention, the type of catalytic reaction is not particularly limited. As a suitable application target of the catalytic reaction apparatus of the present invention, there can be mentioned a tar-containing gas reforming method using the tar-containing gas reforming catalyst as described above. For example, in the presence of a tar-containing gas reforming catalyst as described above, or in the presence of a catalyst after reduction, hydrogen, carbon dioxide, and water vapor are contacted in the tar-containing gas generated when the carbonaceous raw material is pyrolyzed. Thus, the catalytic reaction involves reforming and gasifying the tar-containing gas.

  Further, in the presence of a tar-containing gas reforming catalyst or in the presence of a catalyst after reduction, at least one of the hydrogen, carbon dioxide, and water vapor is added to the tar-containing gas generated when the carbonaceous raw material is pyrolyzed. This is a catalytic reaction in which tar-containing gas is reformed and gasified.

  Here, the tar gasification reaction in which the tar in the tar-containing gas is gasified by catalytic reforming is not necessarily clear because the reaction path is complicated, but between the tar-containing gas and hydrogen introduced from the outside, for example, It is considered that the conversion reaction to light hydrocarbons including methane by hydrogenolysis of condensed polycyclic aromatics in tar as represented by Formula 1 proceeds (when only methane is generated in Formula 1) ) In addition, conversion to hydrogen and carbon monoxide by dry reforming of a condensed polycyclic aromatic compound in tar as represented by Formula 2 between the gas containing tar and carbon dioxide introduced from outside. The reaction proceeds. Further, steam reforming and water gas shift reaction as represented by Formula 3 proceed between the tar-containing gas or water vapor introduced from the outside. The reaction proceeds in the same manner for hydrocarbon components other than tar in the tar-containing gas.

C _n H _m + (2n−m / 2) H ₂ → nCH ₄ (Formula 1)
_{C n H m + n / 2CO} 2 → nCO + m / 2H 2 ( Equation 2)
_{C n H m + 2nH 2 O} → nCO 2 + (m / 2 + n) H 2 ( Equation 3)
Therefore, when producing high calorie gas such as methane, it is desirable to add hydrogen from the outside. Further, when producing hydrogen or carbon monoxide, it is desirable to add carbon dioxide from the outside. Furthermore, when producing more hydrogen, it is desirable to add water vapor from the outside. In addition, the reaction of hydrocarbon components other than tar proceeds according to the above formulas 1 to 3.

  Here, it is preferable to reduce the tar-containing gas reforming catalyst. However, since the reduction proceeds during the reaction, the reduction may not be performed. However, particularly when the tar-containing gas reforming catalyst requires a reduction treatment before the reaction, the reduction condition is that the active metal nickel particles are precipitated in a fine cluster shape, so that the reduction is performed at a relatively high temperature. Is not particularly limited, for example, in a gas atmosphere containing at least one of hydrogen, carbon monoxide and methane, or in a gas atmosphere in which water vapor is mixed with these reducing gases, Alternatively, an atmosphere in which an inert gas such as nitrogen is mixed with these gases may be used. In addition, the reduction temperature is preferably 500 ° C. to 1000 ° C., for example, and the reduction time depends on the amount of catalyst to be charged. For example, 30 minutes to 4 hours is preferable, but the entire packed catalyst is reduced. As long as it is necessary for this, it is not particularly limited to this condition.

  The inlet temperature of the catalyst layer of the catalyst reaction vessel is preferably 500 to 1000 ° C. When the inlet temperature of the catalyst layer is less than 500 ° C., it is not preferable because the catalytic activity when tar and hydrocarbon are reformed to light hydrocarbons mainly composed of hydrogen, carbon monoxide, and methane is hardly exhibited. On the other hand, when the inlet temperature of the catalyst layer exceeds 1000 ° C., it is economically disadvantageous because the reformer becomes expensive, for example, a heat resistant structure is required. The inlet temperature of the catalyst layer is more preferably 550 to 1000 ° C. It is possible to proceed the reaction at a relatively high temperature when the carbonaceous raw material is coal, and at a relatively low temperature when it is biomass.

  Here, even if the tar-containing gas generated by pyrolyzing or partially oxidizing the carbonaceous raw material is a tar-containing gas having a very high hydrogen sulfide concentration such as crude COG discharged from the coke oven, Hydrocarbons can be reformed and gasified. In addition, it can be converted into a useful gas, not just used for conventional fuel applications, and it can lead to higher energy use by converting it to synthesis gas suitable for direct reduction of iron ore. is there.

  According to the catalytic reaction apparatus of the present invention, it is a continuous fixed bed catalytic reaction in which the catalytic reaction vessel (especially between the catalyst and the catalyst) may be clogged due to a solid byproduct, such as a reforming reaction of a tar-containing gas. However, compared with conventional catalyst holders using punched metal or nets, the aperture ratio is significantly higher, so the flow resistance is lower, so the operating cost is lower, and the catalyst holder is blocked by solid by-products. Therefore, the catalyst retainer may be washed as necessary during the catalyst cleaning performed when the catalyst itself is clogged. Therefore, the clogged catalyst retainer is washed as in the conventional case. Therefore, it is possible to eliminate the need to stop the operation of the continuous reaction apparatus.

[Example 1]
(Composition of the entire reaction system)
Coal is supplied from a coal supply device (coal hopper-quantitative supply device) to a heated kiln at a rate of 20 kg / hour, and as a raw material gas, a coal dry distillation gas (including water vapor caused by moisture in the coal) Is generated continuously.
The inlet of the catalytic reactor having the structure as shown in FIG. 2 is connected to the kiln by a heat insulating tube, and the outlet of the catalytic reactor is connected to the induction fan via the scrubber by the heat insulating tube.
Coal dry distillation gas is reformed in a catalytic reaction vessel to produce light gas (hydrogen, etc.), which is a reformed gas, and the atmosphere via flare stack (burns the reformed gas) by an induction fan. Dissipated inside.
The catalytic reaction vessel is accommodated in an electric heating furnace whose furnace temperature is controlled to a constant temperature. The induction fan can adjust the flow rate, and is controlled to a flow rate corresponding to the generation rate of coal dry distillation gas.

(catalyst)
1) Material: Ni _0.1 Ce _0.1 Mg _0.8 O component system Nickel nitrate, cerium nitrate, and magnesium nitrate are precisely weighed so that the molar ratio of each metal element is 1: 1: 8, and heated at 60 ° C. To the prepared mixed aqueous solution, a potassium carbonate aqueous solution heated to 60 ° C. was added to coprecipitate nickel, magnesium and cerium as hydroxides, and the mixture was sufficiently stirred with a stirrer. Thereafter, the mixture was aged for a certain period of time while being kept at 60 ° C., and then subjected to suction filtration and sufficiently washed with pure water at 80 ° C. The precipitate obtained after washing was dried at 120 ° C. and coarsely pulverized, then baked (calcinated) at 600 ° C. in the air, crushed, put in a beaker, added with alumina sol, and a mixer equipped with stirring blades Then, the mixture was transferred to a flask which was mixed well and attached to a rotary evaporator, and the water was evaporated by suction while stirring. The nickel, magnesium, cerium and alumina compounds adhering to the inner wall of the flask are transferred to an evaporating dish, dried at 120 ° C. and calcined at 600 ° C., and then the powder is press molded using a compression molding machine to obtain a molded body. .
The molded body was fired in air at 950 ° C. to prepare a catalyst molded body in which 50% by mass of alumina was mixed with Ni _0.1 Ce _0.1 Mg _0.8 O. As a result of confirming the components of the molded body by ICP analysis, it was confirmed to be a desired component. Moreover, when the molding was measured with the Kiyama-type hardness meter, it was found that a high strength of about 100 N was maintained.

2) Shape and dimensions of catalyst: cylindrical shape with outer diameter of 15mm, inner diameter of 5mm, height of 15mm
3) Amount of catalyst used: 7kg

(Catalytic reactor)
The test was conducted in a catalytic reactor having the structure shown in FIG. However, the catalytic reaction apparatus shown in FIG. 2 was placed inside an electric heating furnace so that it could be heated during the reaction.
Reaction vessel dimensions: 40 mm thick × 450 mm wide × 700 mm high Inlet / outlet: Vented from a rectangular opening with a height of 50 mm and a width of 400 mm to the inflow / outlet pipe of JIS80A.
Material: Stainless steel Pin: A slender rod made of φ5.1 mm and 90 mm long. The top is flat and chamfers 1 mm corner. The arrangement was an isosceles triangle having a base of 16 mm (width direction) and a height of 13.5 mm (thickness direction), and all the pins were welded to the catalyst holder substrate.
Opening ratio: 92%.

(Process conditions)
Kiln temperature: 750 ° C
Electric furnace temperature: 800 ° C
Coal distillation gas flow rate: Average 10Nm ³ / h
Coal dry distillation aeration time: 5 hours

The above catalyst was accommodated in the catalyst reaction apparatus shown in FIG. 2, and a thermocouple was inserted at the center position of the catalyst layer.
Before starting the reforming reaction, the reactor was first heated to 800 ° C. under a nitrogen atmosphere, and then reduced for 30 minutes while flowing hydrogen gas at 80 Nl / min. Thereafter, coke oven gas was adjusted and introduced, and the reaction was evaluated under normal pressure.

(result)
After completion of the test, 20 g of solid carbon was deposited on the catalyst cage substrate, but only a thin solid carbon film was formed on the surface of the catalyst cage, and there was no adhesion of bulk solid carbon to the pins. In addition, the airflow resistance of the catalyst cage was the same as when it was installed.

  Moreover, as a result of investigating the physical properties of the solid carbon deposit, it was found that most of the carbon deposit was amorphous carbon.

[Comparative Example 1]
Instead of the catalyst holder of Example 1, a punching metal having a hole diameter of 6 mm, a plate thickness of 0.8 mm, and an opening ratio of 20% is provided at the inlet to hold the catalyst, and all other conditions are the same as in Example 1. Were tested.

(result)
The test was stopped because the pressure loss in the catalytic reactor exceeded the limit value (6 kPa) after 3 hours of aeration of coal dry distillation gas.

  After the test, the apparatus was cooled, the inlet and outlet were opened, and the catalytic reaction vessel was examined. As a result, all the holes of the punching metal were clogged with solid carbon.

  In this state, 50 Pa (gauge pressure) of nitrogen (a gas that does not cause a catalytic reaction) was supplied to the inlet, and the gas flow rate at the outlet was measured. Next, after removing the solid carbon in the hole of the punching metal with a wire brush, the gas flow rate at the outlet was measured under the same conditions. As a result, the gas flow rate at the outlet after the solid carbon was removed was twice that before the removal. Therefore, in the conventional catalyst holding method, it has been found that the precipitation of solid carbon at the holding portion has a great adverse effect on the air permeability, whereas in the present invention, the catalyst holder hardly affects the air permeability.

[Example 2]
The test was conducted with a catalytic reactor having the structure shown in FIG.
Reaction vessel dimensions: 80 mm thick × 220 mm width × 500 mm high Inlet / outlet: The upper end of the reaction vessel is opened in the JIS 80A outflow pipe, and the lower end is opened in the JIS 150A inflow pipe. The pin holding plate is held at the center height of the inflow pipe, and the exposed portion of the pin outer periphery to the inflow pipe corresponds to the inflow port.

Solid carbon storage space: The inflow pipe area below the pin holding plate corresponds.
Except this, it tested on the conditions similar to Example 1. FIG.
(result)
No bulk solid carbon was observed on the surface of the pin after the test. 10 g of solid carbon was deposited on the pin holding plate and 10 g of solid carbon was deposited in the storage space. Therefore, it was found that the provision of the storage space can suppress an increase in ventilation resistance due to pin burying due to deposition of solid carbon on the pin holding plate.

[Reference Example 1]
To the one prepared by precisely weighing nickel nitrate, cerium nitrate, zirconium nitrate oxide and magnesium nitrate so that the molar ratio of each metal element is 1: 1: 1: 7, and preparing a mixed aqueous solution by heating at 60 ° C., A potassium carbonate aqueous solution heated to 60 ° C. was added to coprecipitate nickel, cerium, zirconium, and magnesium as hydroxides, and the mixture was sufficiently stirred with a stirrer.

Thereafter, the mixture was aged for a certain period of time while being kept at 60 ° C., and then subjected to suction filtration and sufficiently washed with pure water at 80 ° C. The precipitate obtained after washing is dried at 120 ° C and coarsely pulverized, then the material calcined at 600 ° C in the air is crushed and then placed in a beaker. Mix well with a mixer equipped with alumina sol and equipped with stirring blades. The product was transferred to a flask made of eggplant, attached to a rotary evaporator, and sucked with stirring to evaporate water. The nickel, magnesium, and alumina compounds attached to the flask wall are transferred to an evaporating dish, dried at 120 ° C, calcined at 600 ° C, and then pressed into 3mmφ tablets using a compression molding machine. Got the body. The molded body was fired in air at 950 ° C. to prepare a catalyst molded body in which 50% by mass of alumina was mixed with Ni _0.1 Ce _0.1 Zr _0.1 Mg _0.7 O.

As a result of confirming the component of the molded body by ICP analysis, it was confirmed to be a desired component. As a result of this preparation was subjected to XRD measurement, NiMgO, proved to consist of _{MgAl 2 O 4, Ce x Zr} 1-x O 2 phases, the size of each crystallite, 14 nm, 11 nm, 22 nm met It was.

  This catalyst was fixed with quartz wool so as to be located at the center of the reaction tube made of SUS, a thermocouple was inserted at the center position of the catalyst layer, and these fixed bed reaction tubes were set at predetermined positions.

Before starting the reforming reaction, the reactor was first heated to 800 ° C. in a nitrogen atmosphere, and then reduced for 30 minutes while flowing hydrogen gas at 100 mL / min. Thereafter, a simulated gas (hydrogen: nitrogen = 1: 1, containing 2000 ppm of H ₂ S, total flow rate 125 mL / min) of coke oven gas (crude gas) was prepared and introduced into the reactor, and coal dry distillation generated tar As a simulated substance, 1-methylnaphthalene, which is a liquid substance that is actually contained in tar and has a low viscosity at room temperature, is introduced into the reactor at a flow rate of 0.025 g / min as a representative substance, and the reaction is evaluated under normal pressure. did.

  In this reference example, a net was provided at the bottom of the catalyst in the reaction tube and the net was secured by quartz wool so that it did not fall. However, after the test was completed, all the nets received a large amount of solid carbon. It was. Therefore, it was found that when this catalyst was used, a part of the solid carbon easily dropped off and adhered to the net.

  Moreover, as a result of investigating the physical properties of the substances adhering to the net after the test, it was found that they were almost the same as those dropped from the catalyst in Example 1. Therefore, in the reforming reaction using the present catalyst, it is considered that if the apparatus of Example 1 is used, the adhesion and blockage of the product at the catalyst layer holding part can be largely avoided.

[Reference Example 2]
A potassium carbonate aqueous solution heated to 60 ° C. was prepared by accurately weighing the atomic weight% of nickel, magnesium and sodium to 10%, 80% and 10%, respectively, and preparing a mixed aqueous solution by heating at 60 ° C. Was added, nickel, magnesium and sodium were coprecipitated as hydroxides and stirred well with a stirrer. Thereafter, the mixture was aged for a certain period of time while being kept at 60 ° C., and then subjected to suction filtration and sufficiently washed with pure water at 80 ° C.

The precipitate obtained after washing is dried at 120 ° C. and coarsely pulverized, and then baked (calcinated) at 600 ° C. in the air, and then pulverized into a 3 mmφ tablet using a compression molding machine. Press molding was performed to obtain a tablet molding. The molded body was fired in air at 950 ° C. to prepare a Ni _0.1 M _0.1 Mg _0.8 O catalyst molded body.

  This catalyst was fixed with quartz wool so as to be located at the center of the reaction tube made of SUS, a thermocouple was inserted at the center position of the catalyst layer, and these fixed bed reaction tubes were set at predetermined positions.

Before starting the reforming reaction, the reactor was first heated to 800 ° C. in a nitrogen atmosphere, and then reduced for 30 minutes while flowing hydrogen gas at 100 mL / min. Thereafter, a simulated gas (hydrogen: nitrogen = 1: 1, containing 2000 ppm of H ₂ S, total flow rate 125 mL / min) of coke oven gas (crude gas) was prepared and introduced into the reactor, and coal dry distillation generated tar As a simulated substance, 1-methylnaphthalene, which is a liquid substance that is actually contained in tar and has a low viscosity at room temperature, is introduced into the reactor at a flow rate of 0.025 g / min as a representative substance, and the reaction is evaluated under normal pressure. did.

  In this reference example, a net was provided at the bottom of the catalyst in the reaction tube and the net was secured by quartz wool so that it did not fall. However, after the test was completed, all the nets received a large amount of solid carbon. It was. Therefore, it was found that when this catalyst was used, a part of the solid carbon easily dropped off and adhered to the net. Moreover, as a result of investigating the physical properties of the substances adhering to the net after the test, it was found that they were almost the same as those dropped from the catalyst in Example 1. Therefore, in the reforming reaction using this catalyst, if the apparatus of Example 1 is used, it is considered that the adhesion and blockage of the product at the catalyst layer holding part can be largely avoided.

DESCRIPTION OF SYMBOLS 1 Catalytic reaction vessel 2 Catalyst layer 3 Net | punching metal 4 Raw material gas 5 Reformed gas 11 Catalytic reaction vessel 12 Catalyst layer 13 Inflow path 13a Inlet 14 Outlet 14a Outlet 15 Lid 16 Raw material gas 17 Reformed gas 18 Catalyst holding Container 22 Tube 23 Storage space 24 Louver 25 Falling object

Claims (11)

An inflow path for a raw material fluid for catalytic reaction and an outflow path for a reforming fluid;
A catalytic reaction vessel connected to the inflow and outflow paths and containing the bulk catalyst;
A catalyst having a structure in which a bulk catalyst is held by tip portions of a plurality of pins in at least one of connection portions between an inflow path and an outflow path of a catalyst reaction vessel, and a catalytic reaction fluid can flow through a space between the pins. A continuous fixed-bed catalytic reactor characterized by comprising a holding means. The plurality of pins are arranged substantially in parallel, and for all of the pins, the distance between the axes of adjacent pins is
[Pin axis distance]-[Pin outer diameter dimension] <[Minimum mesh opening dimension through which catalyst can pass]
The continuous fixed bed catalytic reactor according to claim 1, wherein the following condition is satisfied.   The continuous fixed-bed catalytic reactor according to claim 1 or 2, wherein a curvature of a contact portion of the pin with the catalyst is smaller than a maximum curvature of the outer surface of the catalyst.   The continuous catalytic reaction apparatus according to any one of claims 1 to 3, wherein the raw material fluid is a gas, and a product of the catalytic reaction contains a solid or a liquid.   The continuous fixed-bed catalytic reactor according to claim 4, wherein a space for storing the solid or liquid product is provided below a contact portion of the pin with the catalyst.   6. The continuous catalytic reaction apparatus according to claim 4, wherein the raw material fluid is a gas containing a hydrocarbon, and a product of the catalytic reaction is a gas and a solid or a liquid.   The continuous fixed-bed catalytic reactor according to claim 6, wherein the feed fluid is a gas containing tar, and the product of the catalytic reaction contains solid hydrocarbon or solid carbon. The catalyst is a composite oxide containing nickel, magnesium, cerium, and aluminum, and a composite oxide not containing alumina, and the composite oxide is a crystal of NiMgO, MgAl ₂ O ₄ , and CeO ₂ . The continuous fixed bed catalytic reactor according to claim 7, comprising a phase. The catalyst is a catalyst composed of a composite oxide containing nickel, magnesium, cerium, zirconium, and aluminum, and the composite oxide includes NiMgO, MgAl ₂ O ₄ , Ce _x Zr _1-x O ₂ (0 <x < The continuous fixed bed catalytic reactor according to claim 7, comprising the crystal phase of 1). The catalyst is
A tar-containing gas reforming catalyst which is a composite oxide represented by aM · bNi · cMg · dO,
a, b, and c satisfy a + b + c = 1, 0.02 ≦ a ≦ 0.98, 0.01 ≦ b ≦ 0.97, and 0.01 ≦ c ≦ 0.97,
d is a value at which oxygen and positive elements are electrically neutral;
M is Ti, Zr, Ca, W, Mn, Zn, Sr, Ba, Ta, Co, Mo, Re, platinum, runium, palladium, rhodium, Li, Na, K, Fe, Cu, Cr, La, Pr. , Nd, and at least one element selected from Nd,
At least one oxide selected from silica, alumina, and zeolite is added to the composite oxide, and the content of the oxide selected from silica, alumina, and zeolite is 1 to 90% by mass with respect to the composite oxide. The continuous fixed bed catalytic reactor according to claim 7, wherein   A continuous fixed bed catalytic reaction method, wherein the catalytic reaction is carried out using the continuous fixed bed catalytic reactor according to any one of claims 1 to 10.