JP2023007820A - Methanation reaction apparatus and methanation reaction method - Google Patents

Abstract

To provide a methanation reaction apparatus capable of properly performing a methanation reaction, and a methanation reaction method using the methanation reaction apparatus.SOLUTION: A source gas inlet 1a is provided at one end of the casing 1A in a cylinder axis direction, and a generated gas outlet 1b is provided at the other end. The casing 1A has a catalyst layer 2 and an inorganic fiber layer 3 as a methanation reaction part, and the catalyst layer 2 and the inorganic fiber layer 3 form layers extending in a direction perpendicular to the direction connecting the inlet 1a and the outlet 1b, and the catalyst layer 2, the inorganic fiber layer 3, the catalyst layer 2, and the inorganic fiber layer 3 are stacked in this order in the direction connecting the inlet 1a and the outlet 1b. A cooling unit 4 is provided to the casing 1. The raw material gas flows into the casing 1A from the inlet 1a, passes through each catalyst layer 2 and the inorganic fiber layer 3, during which the methanation reaction takes place, and the produced gas flows out from the outlet 1b.SELECTED DRAWING: Figure 1

Description

The present invention relates to a methanation reactor equipped with a methanation reaction catalyst and a methanation reaction method using this methanation reactor.

A methanation reaction in which hydrogen and a carbon compound gas are reacted to produce a methane-containing gas is an exothermic reaction with a high reaction rate. Therefore, the methanation reaction apparatus is cooled by water cooling, but there is a problem that the catalyst deteriorates when the reaction temperature rises abnormally or the reaction goes out of control. In addition, when an abnormal temperature rise or a runaway reaction occurs, heat is transferred between the catalysts, and there is a problem that deterioration of the catalyst spreads over a wide range.

As a method of suppressing the reaction speed of the catalyst or suppressing the heat transfer between the catalysts when a runaway reaction occurs, for example, the catalyst is diluted by mixing it with inactive alumina balls or ceramic balls. and a method of alternately filling the catalyst and the alumina balls (for example, Patent Documents 1 and 2).

JP-A-2003-321400 JP 2013-136538 A

Alumina balls and ceramic balls have a high specific gravity and increase the weight of the device. In addition, the alumina balls may crack due to thermal shock when the reaction temperature rises abnormally, and the heat insulating effect may deteriorate.

When starting the methanation reactor, preheating is required to raise the temperature to the optimum reaction temperature, but since alumina balls have a large heat capacity, it takes time to raise the temperature to the optimum reaction temperature.

Further, if the temperature of alumina balls or the like rises due to an abnormal reaction in the methanation reactor, it is difficult to lower the temperature due to their large heat capacity.

In addition, since the alumina balls themselves do not pass gas, the size of the alumina balls is selected when filling the methanation reactor with alumina balls in order to adjust the gas flow rate in the methanation reactor. There is a problem that it is difficult to design and manufacture the device because it is necessary to adjust the gap.

An object of the present invention is to provide a methanation reaction apparatus capable of appropriately conducting a methanation reaction, and a methanation reaction method using this methanation reaction apparatus.

The gist of the present invention is as follows.

[1] A methanation reactor having a methanation reaction section for performing a methanation reaction, wherein the methanation reaction section contains a catalyst and inorganic fibers.

[2] The methanation reactor of [1], wherein the methanation reaction section has a catalyst layer and an inorganic fiber layer.

[3] The methanation reactor has a source gas inlet and a product gas outlet, and the catalyst layers and the inorganic fiber layers are alternately arranged in the direction from the inlet to the outlet. The methanation reactor of [2] described above.

[4] The methanation reactor has a raw material gas inlet and a product gas outlet, and the inorganic fiber layer extends from the inlet to the outlet, The methanation reactor of [2], wherein the reaction section is partitioned into a plurality of regions by the inorganic fiber layer, and each region is filled with a catalyst.

[5] The methanation reactor according to any one of [1] to [4], wherein the inorganic fibers are in the form of a blanket of inorganic fibers.

[6] The methanation reactor of [5], wherein the blanket is a needle blanket.

[7] The methanation reactor of [1], wherein the methanation reaction section is filled with a mixture of the catalyst particles and the inorganic fibers.

[8] The methanation reactor according to any one of [1] to [7], wherein the inorganic fibers are polycrystalline alumina/silica fibers.

[9] The methanation reactor of [8], wherein the polycrystalline alumina/silica fiber has an alumina content of 50% by weight or more.

[10] The methanation reactor of [8], wherein the polycrystalline alumina/silica fiber has an alumina content of 70% by weight or more.

[11] The methanation reactor of [8], wherein the polycrystalline alumina/silica fiber has an alumina content of 94% by weight or more

[12] The methanation reactor according to any one of [1] to [11], wherein the inorganic fibers have an average fiber diameter of 3 to 8 μm.

[13] A methanation reaction method using the methanation reaction apparatus according to any one of [1] to [12], wherein hydrogen and a carbon compound gas are supplied to the catalytic reaction unit, and a generated gas containing methane is produced. A methanation reaction method for producing.

[14] The methanation reaction method of [13], wherein the temperature of the reaction section is 200 to 600°C.

According to the present invention, the inorganic fibers suppress the propagation of heat generated by the catalyst to the surroundings, so that the propagation of abnormal reaction between catalysts and the propagation of abnormal temperature rise between catalysts can be suppressed.

Since inorganic fibers are lighter than alumina balls, it is possible to reduce the weight of the methanation reactor. Since the inorganic fiber has air permeability in a state filled in the reaction section, the air pressure loss in the reaction section is small. In addition, good air permeability allows cooling with relatively low-temperature gas from the upstream side without accumulating heat during an abnormal reaction, and the catalyst can be quickly cooled during an abnormal reaction.

Unlike alumina balls, inorganic fibers do not break even when subjected to repeated thermal stresses, and are excellent in durability.

The methanation reactor of the present invention can prevent deterioration of the catalyst from deteriorating without causing deterioration of the heat insulation layer when an abnormal rise in reaction temperature or runaway reaction occurs. In addition, device design and device manufacturing can be easily performed.

1 is a cross-sectional view of a methanation reactor according to an embodiment; FIG. 1 is a cross-sectional view of a methanation reactor according to an embodiment; FIG. 1 is a perspective view of a methanation reactor according to an embodiment; FIG. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3; FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; FIG. 2 is a perspective view of the inside of a methanation reactor; 1 is a perspective view of a methanation reactor according to an embodiment; FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 7; FIG. FIG. 8 is a cross-sectional view taken along line IX-IX of FIG. 7; 1 is a cross-sectional view of a methanation reactor according to an embodiment; FIG. 1 is a perspective view of a casing of a methanation reactor according to an embodiment; FIG.

Hereinafter, a methanation reactor and a reaction method will be described as an example of the present invention. However, the scope of the present invention is not limited to the embodiments described below.

<Methanation reactor>
The methanation reactor of the present invention has a methanation reaction section containing a catalyst and inorganic fibers.

1 to 10 show an example of the methanation reactor of the present invention.

The methanation reactor 1 of FIG. 1 has a casing 1A in which a catalyst layer 2 and an inorganic fiber layer 3 are alternately provided as a methanation reaction section. Thus, the methanation reaction section preferably has a catalyst layer and an inorganic fiber layer, the catalyst layer is preferably a layer filled with a catalyst, and the inorganic fiber layer is filled with inorganic fibers. Layers are preferred. In this embodiment, the casing 1A has a cylindrical or rectangular tubular shape, and is provided with a cooling section 4 so as to surround the side periphery. The cooling part 4 has a water-cooling jacket structure in this embodiment, and is configured such that, for example, a cooling medium flows in from an inlet 4a and flows out from an outlet 4b. As the cooling medium, an appropriate medium such as water, steam, or oil can be selected according to the temperature and pressure.

A source gas inlet 1a is provided at one end of the casing 1A in the cylinder axis direction, and a generated gas outlet 1b is provided at the other end.
The raw material gas inlet 1a and the generated gas outlet 1b may be attached to the side of the casing instead of the end in the axial direction of the cylinder. Also, the raw material gas inlet 1a and the generated gas outlet 1b may be installed in the middle of the casing by adjusting the gas composition, gas temperature, etc., and the number thereof is not limited.

The catalyst layer 2 and the inorganic fiber layer 3 have a layered shape extending in a direction perpendicular to the direction connecting the inlet 1a and the outlet 1b. The fiber layer 3, the catalyst layer 2, and the inorganic fiber layer 3 are arranged in layers in this order. In FIG. 1, three catalyst layers 2 and three inorganic fiber layers 3 are provided, but the present invention is not limited to this. The length of the inorganic fiber layer 3 may be shorter or longer than that of the catalyst layer 2 . Although not shown, a mesh, a perforated plate, or the like for supporting the catalyst layer 2 and the inorganic fiber layer 3 is disposed closest to the outflow port 1b.

The raw material gas flows into the casing 1A from the inlet 1a, passes through each catalyst layer 2 and the inorganic fiber layer 3, during which the methanation reaction takes place, and the produced gas flows out from the outlet 1b.

In the embodiment of FIG. 2, a plurality of tubular bodies 5 are arranged in the casing 1A in the direction from the inlet 1a to the outlet 1b. In each tubular body 5, catalyst layers 2 and inorganic fiber layers 3 are alternately laminated in the direction from the inlet 1a to the outlet 1b. A space between the tubular bodies 5 is sealed so as not to flow gas. Inorganic fibers may be filled between the tubular bodies 5 . Moreover, it is good also as a structure which flows a cooling medium between tubular bodies.

The tubular body 5 is preferably cylindrical, but may be rectangular. Other configurations of the methanation reactor in FIG. 2 are the same as in FIG. 1, and the same reference numerals denote the same parts.

Also in the methanation reactor of FIG. 2, the raw material gas flows into the casing 1A from the inlet 1a, passes through each catalyst layer 2 and the inorganic fiber layer 3, during which the methanation reaction takes place, and the produced gas is discharged from the outlet. It flows out from 1b.

The methanation reactors shown in FIGS. 3 to 6 have a box-shaped casing 1A in which a catalyst layer 2 and an inorganic fiber layer 3 are arranged in layers. The length of the inorganic fiber layer 3 may be shorter or longer than that of the catalyst layer 2 .

In this embodiment, the casing 1A has a rectangular parallelepiped shape having a pair of main surfaces 1f, one end face 1e of which is provided with a source gas inlet 1a, and the other end face 1e of which is provided with a generated gas outlet 1b. is provided. Cooling portions 4 are provided along the main surfaces 1f, 1f. The cooling unit 4 may also be provided on the casing side surface 1g. The casing 1A preferably has an uneven shape on its surface in order to increase the cooling efficiency. Even in such a case, since the thickness of the inorganic fiber changes flexibly, it can be filled along the unevenness without creating a gap. In particular, by using blanket-shaped inorganic fibers, it becomes possible to flexibly adapt to irregularities.

As shown clearly in FIG. 6, the catalyst layer 2 and the inorganic fiber layer 3 are provided in layers extending in a direction orthogonal to the direction connecting the inlet 1a and the outlet 1b, and the direction from the inlet 1a to the outlet 1b. are provided alternately in the

Also in this embodiment, the raw material gas flows into the casing 1A from the inlet 1a, passes through each catalyst layer 2 and the inorganic fiber layer 3, during which the methanation reaction occurs, and the generated gas flows out from the outlet 1b. do.

The methanation reactors shown in FIGS. 7-9 are different from the methanation reactors shown in FIGS. Therefore, the catalyst layer 2 and the inorganic fiber layer 3 extend in the direction connecting the inlet 1a and the outlet 1b. The length of the inorganic fiber layer 3 may be shorter or longer than that of the catalyst layer 2 .

A space for gas distribution is provided between the inlet 1a and the catalyst layer 2 and the inorganic fiber layer 3, and a space for gas confluence is provided between the outlet 1b and the catalyst layer 2 and the inorganic fiber layer 3. is provided.

Also in this embodiment, the raw material gas that has flowed in through the inlet 1a undergoes a methanation reaction through the catalyst layer 2, and the product gas flows out through the outlet 1b.

In any of the methanation reactors shown in FIGS. 1 to 9, by insulating the catalyst layers with inorganic fibers, it is possible to prevent heat transfer between the catalyst layers due to abnormal reactions without hindering the passage of gas.

The methanation reactor of FIG. 10 is obtained by filling the casing 1A with a mixture 6 of catalyst and inorganic fibers instead of the catalyst layer 2 and the inorganic fiber layer 3 in the methanation reactor of FIG. Other configurations in FIG. 10 are the same as those in FIG. 1, and the same reference numerals denote the same parts. Also in this methanation reactor, by insulating between the catalysts with inorganic fibers, it is possible to prevent the heat transfer between the catalysts due to the abnormal reaction without hindering the passage of the gas.

As shown in FIG. 10, the methanation reactor in which the inorganic fibers and the catalyst are mixed and filled is easy to manufacture.

2, 3 to 6, and 7 to 9, the catalyst layer 2 and the inorganic fiber layer 3 may be replaced by a mixture of the catalyst and the inorganic fiber.

The methanation reactor of FIG. 10 may have a structure in which a plurality of packed layers of a mixture of catalyst and inorganic fibers are provided, and an inorganic fiber layer is arranged between the packed layers. 2, 3 to 6, and 7 to 9, even when a mixture of the catalyst and the inorganic fiber is filled instead of the catalyst layer 2 and the inorganic fiber layer 3, the catalyst and the inorganic fiber It is also possible to provide a plurality of filling layers of a mixture of (1) and to dispose an inorganic fiber layer between the filling layers.

In the present invention, in the methanation reactor of FIG. 10, as shown in FIG. 11, a partition 7 may be provided in the casing 1A, and each space partitioned by the partition may be filled with a mixture of the catalyst and the inorganic fiber. . The partition 7 extends in the direction from the inlet to the outlet. The partition 7 in FIG. 11 has a cross-shaped cross section in the direction perpendicular to the extending direction, and the inside of the casing 1A is divided into four spaces, but it may be divided into 2, 3, or 5 or more spaces. .

When the inorganic fiber layer is arranged as in the methanation reactors of FIGS. Although the pressure loss becomes smaller, the heat insulating effect becomes smaller. These heat insulation methods may be combined. By doing so, it is possible to more accurately control the temperature of the catalyst layer. The arrangement of the inorganic fiber layer is appropriately selected in consideration of the shape and size of the reactor, the thickness and weight of the catalyst layer, the position of the catalyst layer, the internal pressure of the reactor, the gas flow rate, and the like.

Carbon dioxide, carbon monoxide, hydrogen, or the like can be used as the raw material gas. Steam may also be used. By doing so, the generation of carbon on the catalyst surface can be suppressed. When the following catalysts are used, the reaction temperature is preferably 100 to 800°C, more preferably about 200 to 600°C. The pressure is preferably high, preferably 0.2 MPa to 7.0 MPa, more preferably 2.0 to 5.0 MPa. Alumina fibers having an alumina content of 70% by weight or more are preferable because they are less likely to deteriorate even when used at high pressure.

Various catalysts such as Ni-based, Ru-based, and Rh-based catalysts can be used. The average particle size (JIS sieve) of the catalyst is preferably 1 to 1000 nm, particularly about 2 to 8 nm. When the catalyst and the inorganic fiber are mixed and filled, it is preferable to mix 10 to 90 parts by weight, particularly 20 to 40 parts by weight, of the inorganic fiber with 100 parts by weight of the catalyst.

Preferred examples of the above inorganic fibers are described below.

[Inorganic fiber]
The inorganic fibers are not particularly limited, but examples thereof include silica, alumina/silica, and zirconia, spinel, titania and calcia containing these, alone or in combination. Above all, the inside of the methanation reactor becomes a high-temperature hydrogen atmosphere and a high-temperature steam atmosphere, and reduction and decomposition reactions are likely to occur. in particular polycrystalline alumina/silica-based fibers. Polycrystalline alumina/silica-based fibers are particularly preferred alumina/silica fibers having an alumina content of 70 to 99% by weight and a silica content of 30 to 1% by weight. Alumina/silica fiber having an alumina content of 70 to 80% by mass and a silica content of 30 to 20% by mass, that is, a mullite composition or a mullite composition, which has excellent workability and physical strength, and has excellent hydrogen resistance and steam resistance. Fibers close to are preferred. In addition, by using fibers with an alumina content of 70% by mass or more, even if the catalyst reaches a high temperature of, for example, 1200 ° C. or higher due to an abnormal reaction, the alumina fibers do not shrink or deteriorate due to heat, and can maintain their heat insulating effect. can be done. The lower the silica concentration in the fiber, the more difficult it is to be reduced by hydrogen. Therefore, in the case of a reaction site where resistance to hydrogen atmosphere is required, such as the upstream of the methanation reaction, the alumina content is 94 to 99 mass% and the silica content is 6. ~1% by weight alumina/silica fibers, ie a composition close to a pure alumina composition, is preferred. These fibers are appropriately selected in consideration of the thickness and weight of the catalyst layer, the position of the catalyst layer, temperature conditions, cooling conditions, hydrogen concentration, water vapor concentration, and the like.

The form of the inorganic fiber is not particularly limited, and includes the form of a blanket, the form of a bulk, etc. For the reasons of ease of workability, control of the density of the heat insulating layer, and ease of separation during disposal and catalyst layer replacement, the form of the blanket is preferred. In addition, by using inorganic fibers, it is possible to follow repeated dimensional changes due to thermal expansion and contraction of the catalyst layer and casing without generating gaps. In particular, a blanket shape is preferable as an inorganic fiber layer because it is excellent in responsiveness to expansion and contraction. In addition, as the inorganic fiber layer, since it is easy to pass gas while ensuring safety, a mat (needle blanket) is an aggregate of inorganic fibers that does not substantially contain a fiber diameter of 3 μm or less and is subjected to needling treatment. ) is preferred.

Although the average fiber diameter of the inorganic fibers is not particularly limited, it is preferably 3 to 10 μm. More preferred is 5-8 μm. If the fiber diameter is too small, the pressure loss will increase, making it difficult to pass gas before and after production. On the other hand, the thicker the fiber diameter, the lower the pressure loss, and the easier it is for gas to pass before and after production, but there are problems such as lower physical strength and lower heat insulation.

The bulk density of the inorganic fiber mat is not particularly limited, but is preferably 85 kg/m ³ to 250 kg/m ³ , more preferably 90 kg/m ³ to 200 kg/m ³ . Within these bulk density ranges, a sufficient heat insulating effect can be exhibited in the methanation reactor. Also, the temperature rise of the heat insulating layer due to an abnormal reaction is suppressed, and the cooling of the heat insulating layer and the inside of the device progresses quickly. With an appropriate density, it is possible to follow repeated dimensional changes due to thermal expansion and contraction of the catalyst layer and casing without creating gaps. If the catalyst layer or bulk density is too low, the heat insulation effect cannot be sufficiently exhibited, and if the bulk density is too high, the pressure loss will increase.

The thickness of the inorganic fiber mat is appropriately selected, but it is preferably 1 to 30 mm, more preferably 1 to 10 mm, from the viewpoint of workability and strength. If the thickness is too thin, a sufficient heat insulation effect cannot be exhibited, but if the thickness is too thick, there are problems such as an increase in pressure loss and an increase in the size of the device.

1 Methanation Reactor 1A Casing 2 Catalyst Layer 3 Inorganic Fiber Layer 4 Cooling Part 6 Catalyst/Inorganic Fiber Mixture 7 Partition

Claims (14)

In a methanation reactor having a methanation reaction part for performing a methanation reaction,
A methanation reaction apparatus, wherein the methanation reaction section contains a catalyst and inorganic fibers. 2. The methanation reactor according to claim 1, wherein said methanation reactor has a catalyst layer and an inorganic fiber layer. The methanation reactor has a source gas inlet and a product gas outlet,
3. The methanation reactor of claim 2, wherein the catalyst layers and the inorganic fiber layers are alternately arranged in the direction from the inlet to the outlet. The methanation reactor has a source gas inlet and a product gas outlet,
The inorganic fiber layer extends in the direction from the inlet portion to the outlet portion so that the inside of the reaction portion is partitioned into a plurality of regions by the inorganic fiber layer,
3. The methanation reactor of claim 2, wherein each zone is individually packed with catalyst. The methanation reactor according to any one of claims 1 to 4, wherein the inorganic fibers are in the form of a blanket of inorganic fibers. 6. The methanation reactor of claim 5, wherein said blanket is a needle blanket. 2. A methanation reactor according to claim 1, wherein said methanation reaction section is filled with a mixture of said catalyst particles and said inorganic fibers. The methanation reactor according to any one of claims 1 to 7, wherein said inorganic fibers are polycrystalline alumina/silica fibers. 9. The methanation reactor of claim 8, wherein said polycrystalline alumina/silica fibers have an alumina content of 50% by weight or more. 9. The methanation reactor of claim 8, wherein said polycrystalline alumina/silica-based fibers have an alumina content of 70% by weight or more. 9. The methanation reactor of claim 8, wherein said polycrystalline alumina/silica-based fibers have an alumina content of 94% by weight or more. The methanation reactor according to any one of claims 1 to 11, wherein the inorganic fibers have an average fiber diameter of 3 to 8 µm. A methanation reaction method using the methanation reaction apparatus according to any one of claims 1 to 12,
A methanation reaction method for producing a product gas containing methane by supplying hydrogen and a carbon compound gas to the catalytic reaction section. The methanation reaction method according to claim 13, wherein the temperature of the reaction section is 200 to 600°C.

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