JPH0350576B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a catalyst device capable of efficiently carrying out various catalytic reactions in the chemical industry, in addition to catalytic reduction of nitrogen oxides and purification of exhaust gas from internal combustion engines. (Prior art) Various catalytic reaction devices include catalyst devices in which a large number of bead-shaped, pellet-shaped, cylindrical, plate-shaped, and other small catalyst structures are filled irregularly in a fluid pipe. Catalyst devices in which lattice-like or honeycomb-like catalyst structures are regularly arranged are used; however, in the former catalyst device, the reaction fluid passing through the fluid pipes collides with the catalyst structure, causing complex turbulence and causing a reaction. Although the contact efficiency between the fluids and between the reaction fluid and the catalyst structure is improved, a part of the fluid flow path is blocked because it is almost perpendicular to the flow direction of the reaction fluid, resulting in a large pressure loss. The force that tries to remove the catalyst structure works, and sometimes the catalyst structure becomes powder due to wear between the catalyst structures, causing even greater pressure loss, or creating a large channel within the packed bed of the catalyst structure. A phenomenon occurs in which the reaction fluid blows through this channel,
The disadvantage is that the contact efficiency between the reaction fluid and the catalyst surface is reduced, and the latter catalyst device has a large number of through holes parallel to the flow direction of the reaction fluid, which are formed through thin partition walls. Although it has the advantage of reducing loss and increasing the contact surface, the reaction fluids are rectified in the through-holes, which may result in insufficient mixing between the reaction fluids or the contact between the reaction fluid and the catalyst surface. For example, when the reaction fluid is a two-component gas-liquid component, a gas blow-through phenomenon occurs and the contact efficiency between the reaction fluid and the catalyst surface is reduced, making effective use of the large catalyst surface. It didn't reach that point. In addition, in many catalytic reactions, heat is generated or absorbed during the reaction, so it is necessary for the heat transfer within the catalyst packed bed to be good, but in the latter catalyst device, the catalyst packed bed is blocked by a partition wall Because of this, there is no mixing of the reaction fluid in the radial direction, which tends to cause uneven temperature distribution, and the reaction temperature has a large effect on the activity and selectivity of the catalytic reaction.
As a result, the yield of the desired product was reduced. Furthermore, it takes a lot of effort to regularly fill a lattice-like or honeycomb-shaped catalyst structure into a fluid pipe, and it is also necessary to mold the catalyst structure to match the diameter of the fluid pipe. There is,
Moreover, if a plurality of lattice-shaped or honeycomb-shaped catalyst structures are arranged regularly in cavities of a predetermined length between each other in a fluid pipe, the entire catalytic reaction apparatus becomes large and requires a large amount of construction cost. There were some drawbacks that made it necessary. (Purpose of the Invention) The present invention has been completed with the aim of eliminating the above-mentioned drawbacks and providing a catalyst device that has low pressure loss, high contact efficiency with reaction fluid, and can be applied to various uses with little blow-through of reaction fluid. It is what was done. (Structure of the Invention) The present invention provides a honeycomb structure in which a large number of parallel through holes partitioned by partition walls are provided in a honeycomb shape, and the surfaces where the through holes open are formed into a non-planar shape. It is characterized in that the pipes are filled irregularly so as to form flow channels with a network structure. Next, the present invention will be described in detail with reference to the illustrated embodiment. Reference numeral 1 denotes a unit catalyst body having a honeycomb structure, and the unit catalyst body 1 has a large number of parallel through holes 3 partitioned by partition walls 2 in a honeycomb structure. The surface 4 of the block body provided in the shape of the through hole 3 is a curved surface such as a spherical surface, or a non-planar surface having many surfaces that are not perpendicular to the axial direction of the through hole 3, that is, a multifaceted surface. That is. Note that this unit catalyst body 1
Alternatively, the catalyst material may be supported on a honeycomb-structured catalyst carrier as described above by a coating method, or the unit catalyst body 1 may be formed from a mixture of a ceramic material and a catalyst material. Reference numeral 5 denotes a fluid pipe, in which a large number of the unit catalyst bodies 1 are filled in an irregularly stacked state, and the through hole 3 is inserted into the fluid pipe 5.
A channel having a network structure is formed by the pores and the slits between the unit catalyst bodies 1, 1. The material constituting the unit catalyst body 1 must be able to maintain a predetermined shape, so if the honeycomb structure block body itself has a catalytic action, alumina, silica, zeolite, vanadium oxide, etc. Metal catalysts such as metal oxides, copper-nickel, silver-palladium, etc., and polymeric materials represented by ion exchange resins are commonly used. In the case of a catalyst carrier, the catalyst carrier may be formed of any material, and a catalyst substance such as a metal, a metal salt, a metal oxide, a complex catalyst, or oxygen may be supported or fixed thereon. In addition, the means for forming the unit catalyst body is formed by a normal forming method such as press molding or extrusion molding.
If necessary, this may be subjected to cutting or polishing, and the catalyst material may be supported on the catalyst carrier by any means such as coating with the catalyst material in the form of a slurry or by an impregnation method. Furthermore, the shape and size of the unit catalyst body 1, the wall thickness of the partition wall 2, the through hole 3, etc.
The pore diameter and the like are not particularly limited as long as they have the structure described above. When the device configured in this way is used by being incorporated into a catalytic reaction device, etc., like the conventional catalyst device of this kind, the fluid pipe 5 is filled with a large number of unit catalyst bodies 1 irregularly, and This unit catalyst body 1 has a honeycomb structure in which a large number of parallel through holes 3 partitioned by partition walls 2 are provided in a honeycomb shape, and the surface 4 where the through holes 3 open is formed in a non-planar shape. In the fluid conduit 5, a large number of unit catalyst bodies 1 are stacked irregularly so that they are not brought into close contact by each through hole 3 and the non-planar surface 4 in which the through hole 3 opens. A three-dimensionally continuous network structure flow path is formed with gaps between each unit catalyst body 1, 1 and between the unit catalyst body 1 and the inner wall of the fluid pipe 5, and as a result, the fluid pipe The flow of the reaction fluid passing through the channel 5 is complicated and turbulent, and the contact efficiency between the reaction fluids and the surface of the unit catalyst body 1 is extremely high. Since the flow is not blocked, the pressure loss is extremely small.Furthermore, since no large channel is formed in the packed bed of the unit catalyst body 1, no blow-by phenomenon occurs. Next, the results of an experiment conducted to compare the performance of the catalyst device according to the present invention and a conventional catalyst device of this kind will be described. Experimental example: Height 1200mm with a square cross section of 100mm x 100mm
The catalyst-packed layer is made of anatase-type titania, which is formed into a desired shape, and a VOSO ₄ aqueous solution is used to form a catalyst-packed layer that contains 5.5 V ₂ O ₅ components per 100 TiO ₂ components. It was formed from a catalyst body impregnated with the following properties and calcined at 500°C. In addition, as this catalyst body, the example of the present invention is a partition wall 2 whose length, width, and height are 10 mm each and a thickness of 0.4 mm as sample 1.
Nine parallel through-holes 3 are provided in a honeycomb shape, and the surface 4 through which the through-holes 3 open is formed into a spherical shape, as shown in FIGS. 2 and 3. A large number of honeycomb-shaped unit catalyst bodies 1 were used, and the length, width, and height of sample 2 were 10 mm each.
Nine parallel through holes 3 partitioned by partition walls 2 with a thickness of 0.4 mm are provided in a honeycomb shape, and the surface 4 where the through holes 3 open is multifaceted as shown in FIGS. 4 and 5. A large number of polyhedral honeycomb-shaped unit catalyst bodies 1 were used. On the other hand, Sample 3 of the comparative example uses a large number of spherical catalyst bodies with a diameter of 1 mm, Sample 4 of the comparative example uses a spherical catalyst body of 10 mm in diameter, and Sample 5 of the comparative example uses a partition wall with a thickness of 0.4 mm. One columnar catalyst body with a height of 1200 mm was used, which had a honeycomb of many parallel through-holes partitioned by , and Sample 6 of the comparative example had a large number of parallel through-holes partitioned by partition walls of 0.4 mm in thickness. Five short columnar catalyst bodies each having a height of 120 mm and having holes arranged in a honeycomb pattern were used so that they could be arranged at intervals of 120 mm between each other. In addition, in the catalytic reaction experiment, NO = 100 ppm was applied from the inlet of one end of the fluid pipe.
_NH3 =100ppm, _O2 =7vol%, _H2O =10vol%,
Inject a gas consisting of the remainder _N2 , SV = 8000 ¹ /
The reaction was performed at a temperature of 300° C. with HR, UG=3 ^{Nm 2} /s, and the NO concentration at the outlet was measured, and the NO removal rate was calculated using the following formula. NO removal rate (%) = Inlet NO concentration - Outlet NO concentration / Inlet NO concentration × 100 The above experimental results are shown in the table below.

[Table] As is clear from the above table, according to the present invention, the NO removal rate was as high as 99% in both examples, and moreover,
The pressure loss was extremely low at 100 mmAq/m, and it was confirmed that it was highly practical, whereas the comparative example had problems with either the NO removal rate or pressure loss, and was problematic in practice. It was confirmed that Note that the above table is an experimental example only for the catalytic reduction reaction of NO with _NH3 ,
It has been confirmed that it is similarly effective for the complete oxidation reaction of C ₃ H ₈ , and can be applied to hydrogenation reactions, dehydration reactions, decomposition reactions, alkylation reactions, etc. in addition to oxidation reactions and reduction reactions. (Effects of the Invention) As is clear from the above description, the present invention has low pressure loss and high contact efficiency with the reaction fluid.
In addition, there is little blow-through of the reaction fluid, and the unit catalysts can be filled irregularly into the fluid pipes after mass production using any molding method, so it is easy to manufacture and can be provided at low cost. It will greatly contribute to the development of the industry by eliminating the drawbacks of catalyst devices.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of essential parts showing an embodiment of the present invention, FIG. 2 is a partially cutaway front view showing a first embodiment of a unit catalyst body in the present invention, and FIG. FIG. 4 is a partially cutaway front view showing a second embodiment of the unit catalyst body in the present invention, and FIG. 5 is a partially cutaway plan view. 1: Unit catalyst body with honeycomb structure, 2: Partition wall,
3: Through hole, 4: Surface where the through hole opens, 5: Fluid conduit.

Claims (1)

[Scope of Claims] 1. A fluid pipe in which a large number of unit catalyst bodies having a honeycomb structure are provided with a large number of parallel through holes partitioned by partition walls in a honeycomb shape, and the surfaces where the through holes open are formed into a non-planar shape. A catalyst device characterized in that the passages are filled irregularly to form a network-like structure of passages. 2. The catalyst device according to claim 1, wherein the surface through which the through-holes of the unit catalyst bodies open is spherical. 3. The catalyst device according to claim 1, wherein the surface where the through-hole of the unit catalyst body opens is multifaceted. 4. Claim 1 in which the unit catalyst body is a honeycomb-structured catalyst carrier supporting a catalyst substance.
The catalyst device according to item 1 or 2 or 3. 5 Claim 1 in which the unit catalyst body is made of a mixed material of a ceramic material and a catalyst material
The catalyst device according to item 1 or 2 or 3.