KR20000016529A - Support structure for a catalyst - Google Patents

Abstract

PURPOSE: A supporting structure is provided to fix a catalyst structure being formed by multiple channels being arranged longitudinally for passage of flowing gas mixture in a reactor. CONSTITUTION: A support structure (53) for securing a catalyst structure (52) comprising a multiplicity of longitudinally disposed channels for passage of a flowing gas mixture within a reactor, the support structure being comprised of a monolithic open celled or honeycomb-like structure formed by thin strips or ribs of high temperature resistant metal or ceramic which abuts against one end of the catalyst structure, and extends in a direction perpendicular to the longitudinal axis of the catalyst structure to essentially cover an end face (at either the inlet end or outlet end or both) of the catalyst structure with the support structure being secured (54) on its periphery to the reactor wall. The strips or ribs making up the support structure are bounded together to form a unitary structure having cellular openings at least as large as the catalyst structure channel openings. The cellular openings in the support structure are also positioned to be in fluid communication with the channels of the catalyst structure thus affording essentially unaltered gas flow (50) from the catalyst structure through the support structure.

Description

Support structure for catalyst

Various high temperature processes include the desired reaction, for example, complete oxidation of hydrocarbons for emission control, partial oxidation of hydrocarbons, catalytic mufflers for automatic emission control, and catalytic combustion of fuels for use in gas turbines, furnaces, etc. It is known to employ monolithic catalyst structures to facilitate this. Conventional catalyst systems are catalysts used in thermal combustion units for gas turbines to provide low divergence and high combustion rates. In order to achieve high turbine efficiency, high gas temperatures are required. This, of course, imposes high thermal stress on the catalyst monolith employed, which is typically a single or combined metal or ceramic structure consisting of a plurality of channels arranged longitudinally for passage of the flue gas mixture, wherein at least a portion of the channel is combusted. It is coated on the inner surface with a catalyst.

In addition to high thermal stress, the high gas flow rate characteristic of a combustion unit in a gas turbine is characterized by large axial loads or forces on the catalyst structure due to resistance to gas flow in the longitudinally arranged channels of the catalyst structure, ie friction. To push in the direction of gas flow. For example, a multistage monolithic catalyst structure, such as described in US Pat. No. 5,183,401 to Dalla Beta, et al. Has a catalytic combustion reactor having an air / fuel mixture flow rate of about 50 lbs / second at a pressure drop through a catalyst of 4 psi. When employed as a 20 inch diameter catalyst at, the total axial load on the catalyst is about 1,260 lbs.

Combinations exposed to both high temperatures, for example temperatures well above 1,000 ° C. at which the metal monoliths begin to lose strength and temperatures approaching this temperature and the large axial loads (from high gas flow rates) described above, may be used as catalyst support. May cause noticeable movement or deformation. Indeed, in the case where the corrugated foil catalyst monolith is used in a state where the corrugated metal foil is rolled together in a non-nesting form to form a cylindrical, conical structure and the thin layers are not bonded together, The combined high temperature and large axial load from the high gas flow causes the entire structure to overlap in the gas flow direction, especially when the axial force exceeds the sliding resistance between the foils in the rolled structure. For this reason, as a power source for the gas turbine, a support structure for the catalyst structure is provided to fix the structure from movement and deformation along its axial direction in the gas flow direction by a support structure that provides an essential structure at high temperatures without interference with the efficiency of catalytic combustion. Needs to be.

In pending US patent application Ser. No. 08 / 165,966, filed Dec. 10, 1993, the use of an internally cooled support strut or bar at the exit to the catalyst structure is described as a means of supporting the catalyst. have. This approach has the advantage that the support struts are cooled by air or other heat transfer medium, which allows the support struts to have high strength against axial loads even at very high temperatures. However, this approach has the disadvantage that the support struts require a source of cooling air, resulting in a more complicated combustor system design and also requiring the use of high pressure air that is not available for gas turbine machines. An additional disadvantage is that the air cooled struts are spaced quite widely above the surface of the catalyst. This results in high local contact force or stress. In some parts of the catalyst design, this contact force can lead to deformation of the foil beyond the yield strength of the thin catalyst foil. This is clearly not a desirable result and also reduces the availability of air-cooled support struts in high axial load applications.

One possible solution to this foil deformation problem is to provide a cooler support bar so that the contact stress at the exit side of the catalyst is reduced. However, because these air-cooled support bars are quite thick, the majority of their use at the catalyst outlet increases the disturbance of gas flow and also increases the overall pressure drop in the combustor system. In addition, the spacing of the air cooled bars should be very close to reduce contact stress with the catalyst foil.

Another possible approach is to use an uncooled metal support. This causes the support bar to become considerably thinner in cross section, reducing the total cross sectional area resulting in a pressure drop. However, this also has a conceptual problem, i.e. this conventional thickening allows most metals to have a significantly reduced strength at the high operating temperatures of these systems, thus avoiding the use of very thick materials that lead to high disturbances in gas flow. This causes a problem that the load cannot be supported.

The present invention relates to an improved support structure for fixing monolithic catalyst structures used in high temperature reactions such as catalytic combustion in a reaction chamber or reactor. The present invention also relates to a method of using an improved support structure in a high temperature catalytic process such as catalytic combustion for a gas turbine power plant.

1 is a side view of a catalytic combustion reactor in a gas turbine combustor,

2A and 2B illustrate the preparation of a monolithic catalyst structure that can be made available and fixed in a reactor using the monolithic support structure of the present invention;

3A and 3B show components and some cross sections of the support structure of the present invention;

4A-4E are cross-sectional views illustrating various configurations of the catalyst support structure of the present invention;

5, 6, 7 and 8 are schematic views of a catalytic reactor according to the present invention, and

9A and 9B schematically illustrate the effect of axial load due to high gas flow through the catalyst structure on the support structure of the present invention.

Surprisingly, it has been found that uncooled support structures constructed of high temperature resistant metals or ceramics can serve as an excellent means of fixing monolithic catalyst structures, which are designed in a reactor designed for high temperature reactions and high gas flow rates or throughput. It consists of a plurality of channels arranged longitudinally for the passage of the flow gas mixture without causing excessive pressure drop or interfering with the catalytic reaction. This particularly effective support structure consists of a monolithic honeycomb or open cell support structure having at least a cell opening, such as a channel in the catalyst structure, wherein the cell opening has no axial forces acting on the open cell support structure. Thin strips or ribs of high temperature resistant metal or ceramic joined together to provide a single structure extending in contact with the entire exit face of the catalyst structure, with the circumferential edge fixed to the reactor wall in such a way as to be delivered to the reactor wall. And is in fluid communication with the catalyst structure channel.

Despite its open cell appearance, the monolithic honeycomb or open cell support structures of the present invention, when fastened to the reactor wall, are subjected to axial loads or forces acting by catalytic structures operating at high temperatures and at high gas flow rates. With sufficient strength to resist, axial movement or deformation of the catalyst structure is minimized. In addition, the inherent strength of open cell structures permits the use of significantly thin strips or ribs of metal or ceramics in structural frameworks, combined with the use of open cells at least as large as the catalytic reactor channel opening, which is a support structure of the present invention. The high gas flow rate application avoids the pressure drop across the support structure, ie, the catalytic combustion of fuel / air mixtures for continued use in gas turbines. Finally, the honeycomb or open cell nature of the support structure of the present invention provides a plurality of support strips that abut against the catalyst structure over its entire cross-section so that the axial load of the catalyst structure spans the entire monolithic support structure. Spread more evenly to avoid local deformation in the catalyst structure.

The monolithic open cell support structure of the present invention is very preferably located at the outlet side of the catalyst structure to fix the catalyst structure against axial movement in the direction of gas flow through the catalyst structure, while gas flow through the support structure. Their very low resistance to resistance makes them a suitable object to support the inside of the catalyst structure in any countercurrent in case of sudden gas flow disruption. In addition, where a multistage catalyst system is used as disclosed in US Pat. No. 5,183,401 to Dala Beta et al., Supra, the support structure of the present invention may be located at the outlet end of one or more catalyst stages.

Accordingly, one aspect of the present invention relates to a support structure for securing a catalyst structure consisting of a plurality of longitudinally arranged catalyst structures in a reaction chamber having passage inlet and outlet ends of a flow gas mixture, the support structure being Consisting of a monolithic open cell structure in which the walls of the cell are formed by a strip of high temperature resistant metal or ceramic material to provide a cell opening at least as large as the opening formed by the catalyst structure channel at their inlet and outlet ends. Teasing open cell structures are:

(a) at the outlet end of the catalyst structure, or at the inlet end of the catalyst structure or at both the inlet and outlet ends of the catalyst structure;

(b) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with the channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure, Is positioned and formed to cover the end surface; And

(c) an axial load placed on the monolithic open cell structure such that the outer surface is fixed to the reaction chamber wall is transferred to the reaction chamber wall, whereby the axis of the catalyst structure parallel to the longitudinal axis of the catalyst structure Limit the movement of the image.

Another aspect of the invention relates to an improved process for catalytic combustion or partial combustion of fuels that is particularly applicable in the field of gas turbines, wherein the monolithic open cell support structure of the invention is a combustion catalyst in a combustor or reaction chamber. It is used to fix the structure. This process is:

(a) forming a mixture of oxygen containing gas and fuel; And

(b) passing the oxygen-containing gas and fuel mixture as a flow gas stream through a monolithic catalyst structure located in the reaction chamber, the catalyst structure being a plurality of longitudinally disposed passageways for the flow gas flow. A channel consisting of a monolithic opening in which the wall of the cell is formed by a strip of high temperature resistant metal or ceramic material to provide a cell opening at least as large as the opening formed by the catalyst structure channel at the inlet and outlet ends. Stabilized in the reaction chamber by a cell structure, the monolithic open cell structure is:

(Iii) at the outlet end of the catalyst structure or at the inlet end of the catalyst structure or at both the inlet and outlet ends of the catalyst structure;

(Ii) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with the channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure, Is positioned and formed to cover the end surface; And

(Iii) the other surface is fixed to the reaction chamber wall thereby limiting the axial movement of the catalyst structure parallel to the longitudinal axis of the catalyst structure.

Another aspect of the present invention is a method for fixing a monolithic catalyst structure to a reactor or a reaction chamber using the monolithic open cell structure of the present invention, and as an interstage support for a monolithic catalyst employing a multistage catalytic process. It includes a support structure according to the present invention.

The present invention consists of an uncooled support structure that fixes the position of a monolithic catalyst structure in a reaction chamber or reactor, where the catalyst structure is subjected to large axial loads and high temperatures due to high gas flow through the catalyst. The invention also relates to a method of using the support in a catalytic combustion process. More particularly, the present invention relates to a support structure that limits the axial movement of a relatively flexible monolithic catalyst structure in a combustion reactor. In addition to limiting the axial movement of the catalyst structure, this support structure increases the strength of the catalyst with respect to the force imposed by gas flow through the catalyst.

A typical catalytic combustion reactor is shown in FIG. As shown in this figure, the catalyst structure 10 is located in a combustion reactor 1 perpendicular to the flow of an oxygenous gas, typically a mixture of air and fuel, and downstream of the preburner 4, This fuel is introduced into the monolithic catalyst structure via the fuel injector 5. This catalyst structure is positioned in this way to obtain a uniform flow of the air / fuel mixture through the catalyst. In order to maintain the catalyst structure in a safe position in the combustion reactor, any type of support means or structure may be employed to secure the catalyst structure to the combustion reactor, including a support structure which abuts the outlet side 9 of the catalyst structure as a possibility. It is necessary. The outlet side 9 of the catalyst structure is the side at which the partial or complete combustion air / fuel mixture exits the catalyst structure. Thus, the inlet side of the catalyst structure is the side on which the unburned air / fuel mixture is initially introduced into the catalyst structure.

The catalyst structure can be made according to any of the known designs, in particular as a monolithic catalyst structure consisting of a number of parallel longitudinal channels or passageways at least partially coated with a catalyst. Conventional catalyst structures include U.S. Pat. No. 4,870,824 to Young et al., As well as U.S. Pat. 5,232,351; 5,232,351; 5,248,251; 5,248,251; Various publications are disclosed, including 5,250,489 and 5,259,754. The catalyst structure is a honeycomb or spiral rolled corrugated sheet, columnar or other shaped structure of metal or ceramic with longitudinal channels or passageways that allow a high gas space velocity with minimal pressure drop across the catalyst structure. It can be made of a support layer. For example, a helical catalyst structure as shown in FIGS. 2A and 2B can be used. The structure pleats a sheet of metal foil 20 into a corrugated or wavy pattern with depressions 21 and ridges 22 and then rolls it together with a flat metal sheet 24 to form a corrugated sheet 20 as a cylindrical unit. ) And the large spiral portion 25 of the alternating layer of the flat sheet 24. To prepare this catalyst structure, corrugated and / or flat sheets are typically coated on one or both sides with platinum group metal, preferably palladium and / or platinum, before they are rolled together to form a spiral catalyst structure. The illustrated catalyst structure comprises a corrugated metal foil in a straight channel structure combined with a flat foil, while other suitable spiral catalyst structures are wound together in two or more corrugated foil non-nested shapes with a straight or honeycomb structural pattern. Contains things obtained when you lose. The catalyst structure support of the present invention tends to overlap or deform in the direction of gas flow when exposed to high flow rates at a temperature high enough, ie 1,000 ° C. or higher, to soften or otherwise weaken the metal structure. It is particularly useful in the case of metal helical catalyst structures.

Support structure

The support structure of the present invention consists of a monolithic open cell or honeycomb structure formed by thin strips or ribs of high temperature resistant metal or ceramic that abut against one end of the catalyst structure, and on the longitudinal axis of the catalyst structure. It extends in a vertical direction to cover the end face (at the inlet or outlet end or both ends) with the support structure fixed to the reactor wall on its perimeter. The strips or ribs that make up the support structure are joined together to form a single structure having a cellular opening that is at least as large as the catalyst structure channel opening. The cellular opening in the support structure is also positioned to be in fluid communication with the channel of the catalyst structure to provide a constant gas flow from the catalyst structure through the support structure.

While the open cell type of the support structure of the present invention is expected to lead to high strength, especially in high temperature environments, the support structure of the present invention is driven by the tendency of the catalyst structure to move or deform in the direction of gas flow through the catalyst structure. It exhibits a high level of structural integrity and strength to resist axial forces. As noted above for large diameter combustion catalysts, that is, catalysts having a diameter of 10 to 25 inches, typical pressure drops through a catalyst of 4 psi will cause an axial load or force in the gas flow direction of about 600 to 1,600 lbs. Can be. At the axial force in this region and at temperatures of about 1,000 ° C. or higher, the support structure of the present invention exhibits only very small bending and any local deformation of the catalyst structure is made of open cell support monolithic strips. Or because of the uniformity of the support provided by the ribs. Thus, the support structure of the present invention has the two advantages of being able to support a large axial load while still having an open structure with very low resistance to gas flow through the structure.

The monolithic open cell support structure of the present invention may be made of any other structural material as well as ceramic or metal designed to provide sufficient structural integrity and strength under high temperatures and high loads. High temperature resistant metal materials that can be employed to be available in the support structures of the present invention include high temperature resistant steel alloys such as nickel, cobalt or chromium alloys or other alloys proportioned for the required temperature service, as well as intermetallic materials and metal ceramics. Includes composites. Of course, different materials may be employed depending on the location of the support structure and the temperature and axial forces it will receive. For example, support structures that may be employed at the inlet end of the catalyst structure (at the initial stage of the multistage catalyst system) may be different in structural material without being subjected to the same temperature and force applied at the outlet end of the final catalyst stage. . Preferred metallic materials of the structure typically contain about 20% Cr and about 5% Al and the remainder are Alpha IV, Kawasaki Steel, available from Allegheny Ludlum (Pittsburgh, Pennsylvania). And FeCrAl alloys made of Fe such as Riverlite R20-5SR available from Steel, Kobe, Japan, and Aluchrom Y from VDM (Werdohl, Germany). Another preferred metal alloy is NiCrAl, a nickel-based superalloy containing about 20% Cr and about 5% Al, with the remainder being Ni such as Henis 214 from Haynes International (Cocommo, Indiana). . Suitable ceramic materials are Cordierite monolithic, available from Celcor cordierite from Corning Glass Walk (Corning, NY) and from NGK Locke (Southfield, Mich.). substrates).

The support structures of the present invention may be constructed or fabricated using any conventional technique to form monolithic honeycomb structures made of strips or ribs of ceramic or metal material joined together to form a single structure. For example, the structure may be cast as a single unit in a suitable mold or the structure may be formed by joining together a series of strips or ribs that are preformed or curved to provide the desired cellular open structure when joined together. have. In this regard, FIGS. 3A and 3B illustrate the manufacture of a portion of the support structure according to the invention, wherein the structure is a metal monolith with a hexagonal cell opening. This support structure is made of a thin metal strip 30 formed of corrugated strips with flat facets 31 and valleys 32. These corrugated strips are placed together to form the hexagonal or honeycomb structure shown in FIG. 3B, wherein the contacting flat portions of the strip are joined together by welding or soldering 33 to form a single or monolithic structure. . When formed into a complete support structure, the illustrated honeycomb structure is surrounded by a circular strip of metal (not shown) that is joined to the periphery of the honeycomb in such a way that the corrugated strips making the honeycomb are joined together. A circular strip of metal or metal frame is applied to provide the support structure, which cross section spans the same space as the cross section of the cylindrical catalyst structure in a direction perpendicular to the gas flow through the catalyst structure. Where metal strips are forming a support structure, it is desirable to use soldering techniques to join the strips together, since it has been shown to be stronger than welding and to provide a more uniform structure, but The use of welding as a method is not excluded. Welding and soldering can also be used jointly as a method of joining these strips together.

The cellular openings in the support structure of the present invention are considerably uniform in cross-sectional area, allowing sufficient contact between adjacent strips or ribs that define the edges of the cellular openings so that a strong bond between the strips or ribs can be made if various It may have a shape. Preferably, the cells of the open cell structure may be polygonal, elliptical or circular in shape, and the polygonal cell is preferably trapezoidal, triangular, rectangular, square or hexagonal in shape. Most preferably, the cellular opening is hexagonal in terms of bonding strength that can be made between adjacent strips or ribs and ease of manufacture. In this regard, FIGS. 4A-4E illustrate end views of several different open cell structures that can be applied in the support structure of the present invention for a cylindrical catalyst structure similar to that shown in FIG. 2B. 4A illustrates a cross-sectional view of a support structure with hexagonal cell openings 40 surrounded by and bonded to a circular strip 41 that makes up the framework of the support structure, while FIG. 4B is shown by a circular frame 43. A similar cross-sectional view of a support structure having a rectangular cell opening 42 enclosed is illustrated. 4C illustrates a cross-sectional view of the support structure according to the present invention wherein the cellular opening 44 is again circular in shape in the circular frame 45. Finally, Figures 4D and 4E illustrate the support structure of the present invention with a trapezoidal cell opening 46 or a triangular cell opening 48, each easily surrounded by circular frames 47 and 49, respectively.

As pointed out above, it is important that the cellular openings in the support structures of the present invention are at least as large in cross-sectional area as the cross-sectional area of the individual longitudinal channels made of the catalyst structure, regardless of their specific shape. Preferably, the cell opening is 1.1 to 200 times larger than the opening of the catalyst structure in fluid communication with the cell opening to minimize pressure drop or other flow obstruction problems. With conventional monolithic catalyst structures applied to the catalytic combustion process, the open cell or cell opening of the support structure of the present invention has an advantageous cell size or cross-sectional area or average cell size of about 0.03 in ² to about 2.0 in ² . And an average cell size in the range of about 0.05 in ² to about 0.2 in ² is most preferred.

Strip or rib thickness (defined as the cross-sectional size of individual strips measured in a direction perpendicular to the gas flow) to make the support structure of the present invention, and width (length in the gas flow direction) of the strip or rib to make the new support structure. Limited to the size of the strip, as determined by the process parameters in which the support structure is to be used and various factors related to the size of the reaction chamber and catalyst structure. For example, the thickness of the metal or ceramic strip depends on the flow disturbance (pressure drop) that can be tolerated, the axial load to be supported, the diameter of the catalyst structure, the cell size of the open cell structure and the expected temperature to occur in use. Similarly, the width of the support structure according to the invention depends on such factors as the axial load to be supported, the size of the catalyst structure, the expected temperature to be met and the space allowed in the reaction chamber for the support structure. In order to avoid excessive pressure drop and to compensate for other process variables typically encountered, the strip or rib made of the support structure should be about 0.5 to about 20 times as thick as the walls of the channel discharged in the longitudinal direction of the catalyst support. For metal structures the strip thickness is preferably about 1 to about 10 times as thick as the catalyst channel wall and for ceramic structures the strip or rib thickness is about 2 to about 20 times as thick as the channel wall of the catalyst structure. In the case of a catalytic structure, the strip thickness of the metal support structure of the present invention is suitably in the range between about 0.0001 in and about 0.01 in, and the metal strip thickness between about 0.002 in and about 0.03 in is preferred and about 0.005. Most preferred is a range from in to about 0.02 in. For tactile loads that are typically encountered in catalytic combustion, it is desirable to use metal strip widths in the support structures of the present invention between about 0.25 in and about 3 in, whereas strip or rib widths if ceramic support structures are applied Silver is appropriately about 0.75 in to about 4 in. In each case, however, the specific width and thickness selected depend on the actual yield and creep strength and the degree of local stress of the material of the selected structure.

The thickness of the strip or rib making the support structure of the present invention coupled with the cell density or cell opening size in this structure has a direct effect such that gas flow into and out of the support structure is disturbed by the support structure. Suitably, these factors are controlled such that the disturbances provided by any single support structure in accordance with the present invention are about 25 percent or less. Preferably, the flow obstruction is between about 5 to 15 percent so as not to excessively impede the gas flowability of the gas reaction mixture. In addition, the flow passages in this support structure are preferably straight channels with relatively smooth walls to minimize turbulence in the gas flow and achieve the lowest resistance to the gas flow.

Typical applications of the support structures of the present invention in catalytic reactors are shown in FIGS. 5, 6 and 7. In FIG. 5, which shows a single stage catalytic reactor as used in a catalytic combustion system, the gas reaction mixture 50 has a reaction chamber partitioned by a reactor wall 51, which in the case of a catalytic combustor, becomes a combustor inner wall. And pass through a catalytic reactor containing a catalyst structure 52 consisting of a plurality of parallel longitudinal channels for the passage of the gas reaction mixture. The catalyst structure is extruded inwardly to form a ledge on which the outer or circumferential edge of the support structure lies and is secured to the reactor wall by a lip or ridge 54 attached to or formed as part of the reactor wall. Is fixed in the reaction chamber by a monolithic open cell support structure (53). In this way, any axial load acting on the support structure by gas flow through the catalyst structure is transferred from the support structure to the reactor wall.

6 illustrates a similar reaction system except that a two stage catalytic reactor is applied. In this case, the gas reaction mixture 60 has a reaction chamber partitioned by the reactor wall 61 but in this case two monolithic catalyst structures 62 and 63 consisting of first and second stage catalytic reaction systems. Flows back into the catalytic reactor and in each case the catalyst structure is supported by the support structures 64 and 65 of the present invention positioned to abut against each outlet end or face of the two catalyst structures. Is fixed at. The two support structures shown are secured to the reactor wall by inwardly lip or ridges 66 and 67 so that an axial load on the catalyst structure is delivered to the support structure so that the support structure delivers the load to the reactor wall. .

Finally, Figure 7 shows a two stage catalytic reactor having no support between the stages but being secured to the support structure of the present invention on its inlet side and on its outlet side. Here again, the gas reaction mixture 70 has a reaction chamber partitioned by a reactor wall 71 and in a catalytic reactor containing a multistage catalyst composed of two catalyst monoliths 72 and 73 abutting against each other. Each of these units has a number of parallel longitudinal channels in fluid communication with the channels in the other catalytic stages. The two-stage catalyst structure is located at both the outlet end 74 of the second stage of the catalyst structure and the inlet end 75 of the first stage of the catalyst structure, sandwiching the catalyst structure into the reaction chamber and moving the catalyst structure along the axis. It is fixed in the reaction chamber by the support structure of the present invention which is fixed in either direction from. The support structure at the outlet end of the two-stage system and the support structure at the inlet end are secured by ribs or ridges 76 and 77 extending inwardly from the reactor wall to act to transfer any axial force to the reactor wall.

The use of inwardly extruded ribs or ridges on the reactor wall, on which the support structure of the present invention is placed, has a distinctly operational advantage over welding or otherwise securing, for example, the perimeter of the support to the reactor wall. It can accommodate a support structure that accommodates thermal expansion of the support, which can be generated upon contact with hot gas flow by providing free space without the ridge or lip extending far to the reactor wall. Preferably, the support structure of the present invention is sized and ridges or ribs are used such that the support can extend up to 2% of the diameter in the circumferential direction without pressing or contacting against the reactor walls. In a preferred embodiment, the ribs or ridges on the reactor wall on which the downstream or outlet side of the support structure is placed, as shown in FIGS. 5, 6 and 7, may be doubled at a position just before the inlet or face of the support structure. Can actually form slots in which the support structure can fit but still have degrees of freedom to accommodate thermal expansion. With this preferred means of securing the support structure to the reactor wall, any sudden back pressure on the support structure will not cause the potential of the support structure.

An alternative method of securing the support structure of the invention to the reactor wall is shown in FIG. 8, which illustrates a single stage catalytic reactor where the gas reaction mixture 80 is defined by the reactor wall 81. Passes through a catalytic reactor containing a catalyst structure 82 having a reaction chamber and fixedly held in the reactor by the open cell support structure 83 of the present invention. In a preferred embodiment of the invention, the support structure that does not extend far to the reactor wall is rivets that extend through the reactor wall into a series of cavities of the support structure that are of sufficient depth to allow thermal expansion of the support structure when exposed to hot reaction gases. It is attached to the reactor wall by 84. That is, the rivet leaves a suitable opening at the end of the rivet to allow for different thermal expansion of the support structure while penetrating through the support structure for a length sufficient to securely hold the support structure.

As noted above, one of the important and surprising advantages of the support structure of the present invention is that the support structure is subjected to high axial loads or forces as a result of high gas flow through the monolithic catalyst structure that the support structure supports. Excellent strength to show. That is, when a high axial load acts on the support structure, the support structure tends to bend in the same direction as the axial force is being applied, and in the case of the support structure of the present invention, Amazing elasticity is maintained even when the structure is subjected to high thermal stresses in addition to high axial loads. For the support structure of the present invention, this shows a catalytic reactor in which the catalyst structure 90 is fixed in the reaction chamber wall 91 by the support structure 92 of the present invention at the outlet side of the catalyst structure. 9B, which support structure is secured to the reactor wall by a lip or ridge 93 that is pushed inward into the reaction chamber. In this case, the gas flow 94 through the catalyst structure is such that the axial force acting on the support structure causes bending or curvature of the support structure in the direction of the gas flow (shown enlarged in FIG. 9B). For the purposes of the present invention, this deflection is expressed or limited as strain for any given support structure, where "strain" refers to a standard or conventional load from the axial gas flow on the catalyst, i.e. the diameter of the support structure (or It is defined as the ratio (number) of bending or curvature in the support structure occurring at 4 psi divided by the length of the non-circular support). This deflection or curvature is shown as shown in FIG. 9B as the difference between the load on the standard axis, i. For the support structure of the present invention this strain is suitably from about 0.00001 to 0.05 and preferably in the range of from about 0.001 to 0.02. This very low strain, maintained equally for the support structures of the present invention exposed to temperatures in the range of about 1000 ° C., is subject to high axial load characteristics of the process, which is catalytic combustion operating at very high gas flow rates. Excellent strength of the supporting structure according to the present invention.

fair

As noted above, the support structures of the present invention can be used in processes for catalytic combustion of hydrocarbons or other combustible fuels, such as methane, ethane, H ₂ or CO / H ₂ mixtures. In this process, an oxygen containing gas such as air is mixed with the hydrocarbon to form a combustible oxygen / fuel mixture. This oxygen / fuel mixture is placed in the reaction chamber to pass the monolithic catalyst structure as flowing gas to combust the oxygen / fuel mixture and form a hot, partially or fully burned gas product.

Various catalyst structures can be used in this process. For example, an integral heat exchanger surface having a catalyst structure described in US Pat. No. 5,250,489, or a graded palladium-containing partial combustion catalyst and a process for use, is described in US Pat. No. 5,248,251. Palladium containing partial combustion treatment catalysts as graded in US Pat. No. 5,258,349 can be used in the present invention. This process may also include the complete combustion of the fuel or partial combustion of the fuel described in pending US application Ser. No. 08 / 088,614, titled Combustion Mixture. The process can also be a multistage process, in which the fuel is subjected to specific catalyst and catalyst structures in several stages, as described in US Pat. Burning step by step. The six patents and one patent application are described herein by reference.

This process involves stabilizing the position of the catalyst structure in the reaction chamber to prevent axial movement of the catalyst structure. The catalyst structure is stabilized in the reaction chamber by a monolithic open cell type structure wherein the walls of the cell are formed by strips of high temperature resistant metal or ceramic material, at least by openings formed by the catalyst structure channels at the inlet and outlet ends. Providing a large cell opening, the monolithic open cell structure

(a) at the outlet end of the catalyst structure, or at the inlet end of the catalyst structure or at both the inlet and outlet ends of the catalyst structure;

(b) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with the channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure, Is positioned and formed to cover the end surface; And

(c) The outer surface is fixed to the reaction chamber wall thereby limiting the axial movement of the catalyst structure parallel to the longitudinal axis of the catalyst structure.

It is noted that those skilled in the art are envisioned as equivalents of the devices described in the following claims and that these equivalents do not depart from the spirit and scope of the claimed invention.

Claims (30)

A support structure for securing in a reaction chamber a catalyst structure consisting of a plurality of channels arranged longitudinally with an inlet end and an outlet end for passage of a flowing gas mixture, said support structure being connected to the catalyst structure channels by their inlet. A monolithic open cell structure in which the walls of the cell are formed by strips of high temperature resistant metal or ceramic material to provide a cell opening at least as large as at least an opening formed at the end and the outlet end, the monolithic open cell structure : (a) at the outlet end of the catalyst structure, or at the inlet end of the catalyst structure or at both the inlet and outlet ends of the catalyst structure; (b) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with a channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure such that Is positioned and formed to cover the end surface; And (c) the outer surface of the monolithic open cell structure is fixed to the reaction chamber wall such that an axial load located on the monolithic open cell structure is transferred to the reaction chamber wall, thereby paralleling the longitudinal axis of the catalyst structure. A support structure for limiting axial movement of one said catalyst structure. The support structure of claim 1, wherein the monolithic open cell structure is located at the outlet end of the catalyst structure. 2. The support structure of claim 1, wherein the monolithic open cell structure is located at both the inlet and outlet ends of the catalyst structure. 4. A support structure according to claim 1, 2 or 3, wherein the cells of the open cell structure are polygonal, oval or circular in shape. 5. The support structure of claim 4, wherein the cell is polygonal in shape. 6. The support structure of claim 5, wherein the polygonal cell is in the shape of a trapezoid, triangle, rectangle, rectangle or hexagon. 2. The support structure of claim 1, wherein the flow blockage provided by any single monolithic open cell structure at the inlet or outlet of the catalyst structure is less than about 25%. 8. The support structure of claim 7, wherein the flow blockage is between about 5 and about 15%. 2. The support structure of claim 1, wherein the metal or ceramic strip constituting the monolithic open cell structure is about 0.5 to 20 times thicker than the walls of the channels disposed longitudinally of the catalyst structure. 10. The support structure of claim 9, wherein the strip of the monolithic open cell structure and the catalyst structure channel wall are made of a high temperature resistant metal material. 10. The support structure of claim 9, wherein the width of the strip comprising the monolithic open cell structure is between about 0.25 and 4 inches. 12. The support structure of claim 1, 2, 3, 10 or 11, wherein the strain for the monolithic open cell structure is between about 0.0001 and about 0.05. The support structure of claim 1, wherein the open cell of the monolithic open cell structure has an average cell size (cross-section) ranging from about 0.03 in ² to about 2.0 in ^2. The monolithic open cell structure of claim 1, wherein the monolithic open cell structure is secured to the reaction chamber wall to hold the monolithic open cell structure in place while allowing different thermal expansion of the monolithic open cell structure toward the reaction chamber wall in an outward direction. The support structure, characterized in that fixed to the wall of the reaction chamber by the attached means. 15. The interior of the reaction chamber wall of claim 14, wherein the attachment means (a) one side of the outer surface of the monolithic open cell structure lies in a slidable manner to accommodate different thermal expansion of the monolithic open cell structure. Inward extruded in; Or (b) a series of strings extending through the reaction chamber wall into the cavity on the outer surface of the monolithic open cell structure with a difference in the length of the rivet and the depth of the cavity to accommodate the different thermal expansion of the monolithic open cell structure. A support structure, characterized in that selected from rivets. A catalyst structure consisting of a plurality of channels arranged longitudinally with an inlet end and an outlet end for passage of a flow gas mixture, the flow gas mixture into the reaction chamber at the outlet end of the catalyst structure or at both the outlet end and the inlet end of the catalyst structure. 17. A method of securing in said reaction chamber the catalyst structures in which the insertion is made, the method comprising: providing a cell opening at least as large as openings formed at their inlet and outlet ends by a catalyst support structure channel by strips of high temperature resistant metal or ceramic material; The monolithic open cell structure in which the walls of the cell are formed: (a) while the cell opening of the monolithic open cell structure is in fluid communication with the channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure to Is positioned and formed to cover the end surface; And (b) the outer surface of the monolithic open cell structure is fixed to the reaction chamber wall such that an axial load located on the monolithic open cell structure is transferred to the reaction chamber wall, thereby limiting the axial movement of the catalyst structure. Characterized in that. A method of combusting a hydrocarbon or other combustible fuel at least partially combusted to form a hot gas product, the method comprising: (a) forming a mixture of oxygen containing gas and fuel; And (b) passing the oxygen-containing gas and fuel mixture as a flow gas stream through a monolithic catalyst structure located in the reaction chamber, the catalyst structure being longitudinally disposed for passage of the flow gas flow. A plurality of channels, wherein the catalyst structures are formed by walls of cells of high temperature resistant metal or ceramic material to provide a cellular opening that is at least as large as at least an opening formed at their inlet and outlet ends by the catalyst structure channel. Stable in the reaction chamber by a monolithic open cell structure, the monolithic open cell structure is: (Iii) at the outlet end of the catalyst structure or at the inlet end of the catalyst structure or at both the inlet and outlet ends of the catalyst structure; (Ii) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with the channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure to Is positioned and formed to cover the end surface; And (Iii) an outer surface of the monolithic open cell structure is fixed to the reaction chamber wall thereby limiting the axial movement of the catalyst structure parallel to the longitudinal axis of the catalyst structure. 18. The method of claim 17, wherein the monolithic open cell structure is located at the outlet end of the catalyst structure. 18. The method of claim 17, wherein the monolithic open cell structure is located at both the inlet and outlet ends of the catalyst structure. 20. The method of claim 17, 18 or 19, wherein the cells of the open cell structure are polygonal, oval or circular in shape. 21. The method of claim 20, wherein the cell is polygonal in shape. 22. The method of claim 21, wherein the polygonal cell is in the shape of a trapezoid, triangle, rectangle, rectangle or hexagon. 18. The method of claim 17, wherein the flow blockage provided by any single monolithic open cell structure at the inlet or outlet of the catalyst structure is less than about 25%. 24. The method of claim 23, wherein said flow blockage is between about 5 and about 15%. 18. The method of claim 17, wherein the metal or ceramic strip constituting the monolithic open cell structure is about 0.5 to 20 times thicker than the walls of the channels disposed longitudinally of the catalyst structure. 27. The method of claim 25, wherein the strip of the monolithic open cell structure and the catalyst structure channel wall are made of a high temperature resistant metal material. 27. The method of claim 25, wherein the strip of the monolithic open cell structure is between about 0.25 and 4 inches in width. 28. The method of claim 17, 18, 19, 26 or 27, wherein the strain for the monolithic open cell structure is between about 0.0001 and about 0.05. 18. The method of claim 17, wherein the open cells of the monolithic open cell structure have an average cell size (cross section) ranging from about 0.03 in ² to about 2.0 in ² . A support structure for securing in a reaction chamber a multistage catalyst structure consisting of a plurality of longitudinally arranged longitudinally arranged passageways from each stage for passage of a flowing gas mixture, said support structure being a catalyst structure. Consisting of a monolithic open cell structure in which the walls of the cell are formed by strips of high temperature resistant metal or ceramic material to provide cell openings at least as large as the openings formed at their inlet and outlet ends by channels. Teasing open cell structures are: (a) at the outlet end of each stage of the catalyst structure or at the inlet end of the first stage of the catalyst structure or at the outlet end of one or more catalyst structures comprising the final catalyst stage in the catalyst structure; (b) in a state in which the cell opening of the monolithic open cell structure is in fluid communication with a channel of the catalyst structure, it abuts against one end of the catalyst structure and extends in a direction perpendicular to the longitudinal axis of the catalyst structure such that Is positioned and formed to cover the end surface; And (c) the outer surface of the monolithic open cell structure is fixed to the reaction chamber wall such that an axial load located on the monolithic open cell structure is transferred to the reaction chamber wall, thereby paralleling the longitudinal axis of the catalyst structure. A support structure for limiting axial movement of one said catalyst structure.