MXPA01003980A - Production of hydrogen-containing gas streams - Google Patents

Abstract

Steam-reforming is accomplished by use of a steam-reforming catalyst (preferably supported on a particulate support), with such supported catalyst being supported on a mesh, e.g., as a coating or entrapped in the interstices of the mesh. Alternatively, the mesh may be formed from a steam-reforming catalyst.

Description

PRODUCTION OF GAS CURRENTS CONTAINING HYDROGEN This application claims the priority of U.S. Provisional Application 60 / 107,127, filed November 5, 1998. This invention relates to the production of a hydrogen-containing gas by the catalytic reformation of a hydrocarbon alkylation material. catalytic of a hydrocarbon feedstock to produce a hydrogen-containing gas, in general, said reform is achieved by the use of a reforming gas such as steam and / or carbon dioxide in particular steam in the presence of a reforming catalyst appropriate. In general, this feedstock comprises methane and the hydrogen-containing gas contains hydrogen and monoxide d? carbon, with said gas being frequently referred to in the field as a "synthesis gas". The steam reforming reaction is endothermic and ST operates at elevated temperature so that the equilibrium favors the production of hydrogen. The heat required for the reaction of ST endothermic reform supplies by pre-heating the feed and heating during the particular reform process, »AxMéÉ? MAe! Iih? É¡¿ / r'- 'the reforming reaction is achieved in a reactor frequently referred to in the industry as a steam reformer. In general, the steam reforming reactor is a tubular reactor where the tubes are heated in a furnace turned on However, other reactor configurations are also possible v un-ignited tubular reactors or adiabatic pre-heated packed beds The present invention is directed to improving the steam reforming process for conversion of a feed material of hydrocarbon in a synthesis gas According to one aspect of the present invention a synthesis gas (a gas containing hydrogen, and also generally containing carbon monoxide) is produced by reacting steam and a hydrocarbon with the hydrocarbon preferably being methane , in the presence of a steam reforming catalyst, where the steam reforming catalyst is supported by a mesh or material Like mesh, or the catalyst is in the form of a mesh ie the mesh is formed from a catalytic material The term "supported on the mesh" includes coating the catalyst on the mesh as well as trapping the catalyst in the interstices of the mesh The catalyst that is supported on the mesh, in a preferred embodiment, is comprised of a catalyst. of steam reforming supported on a particulate support with the sustained vapor reforming catalyst being supported on the mesh. More particularly, the mesh-like material is comprised of fibers or wires, such as a wire or fiber mesh, a metal felt or gauze, metal fiber filter or the like. The mesh-like structure may be comprised of a single layer, e.g., a knitted wire structure or a woven wire structure, or may include more than one layer of wires; and preferably it is comprised of a plurality of layers of wires or fibers to form a three-dimensional network of materials. In a preferred embodiment, the support structure is comprised of a plurality of layers of fibers that are randomly oriented in the layers. One or more metals can be used when producing a metal mesh. Alternatively, the mesh fibers can be formed from or include materials other than metals alone or in combination with metals; e.g., carbon or metal oxides or a ceramic. In a preferred embodiment, the mesh includes a metal. In the case where the mesh supports the catalyst, the material forming the mesh is preferably non-catalytic with respect to steam reforming. As indicated above, in one embodiment, the material forming the mesh is a steam reforming catalyst. In a preferred embodiment wherein the mesh-like structure is comprised of a plurality of layers of fibers to form the three-dimensional network of materials, the thickness of said support is at least five microns, and usually does not exceed ten millimeters. According to a preferred embodiment, the thickness of the network is at least 50 microns and more preferably at least 100 microns and generally does not exceed 2 millimeters. In general, the thickness or diameter of the fibers forming the plurality of fiber layers is less than about 500 microns, preferably less than about 150 microns, and more preferably less than about 30 microns. In a preferred embodiment, the thickness or diameter of the fibers is from about 8 to about 25 microns. The three-dimensional mesh-like structure can be produced as described in U.S. Patent Nos. 5,304,330; 5,080,962; 5,102,745 or 5,096,663. It should be understood, however, that such a mesh-like structure can be formed by M? Ni ^ lí? Í procedures other than that described in the aforementioned patents In the preferred embodiment where the mesh-like structure supports a steam reforming catalyst on a particulate support, the support of particulate catalyst is a support porous and in a preferred embodiment, has a surface area that is greater than 1 m2 / g, and preferably a surface area greater than 5 m2 / g. In most cases, the surface area does not exceed 100 mVg. The surface area is measured by the Brunauer Emmett and Teller method (BET). The support is a porous support which is resistant to heat, and as representative examples of these supports may be mentioned alumina, silicon carbide, silica, zirconia, titania, calcium aluminate, calcium aluminum titanate, and silica / alumina support , etc. The catalyst support on which the steam reforming catalyst is supported is a support that is in the form of particles (with said supported catalyst being supported on the mesh-like structure). The term "particles" as used herein includes and encompasses spherical particles, elongated particles, fibers, etc. In general, the particulate support has an average particle size of at least 0 5 microns and no larger than 20 microns even when larger particles may be used. In some cases, the particle size may be as low as 0.002 microns. wherein the support particles are entrapped, the particles are not greater than 300 μm, preferably not greater than 200 μm and more preferably not greater than 100 μm when the catalyst is coated on the mesh, the particulate support in the Most cases do not exceed 10 microns The reforming steam catalyst may be of a type known in the art In general, this catalyst includes nickel, ruthenium or rhodium, with or without promoters such as alkali metals In accordance with an aspect of the present invention, the steam reforming catalyst (with or without a support) is supported on the mesh-like structure in an amount of at least 5%, and preferably at least 10%, with the amount of catalyst generally not exceeding 60% and not more generally exceeding 50%, all by weight, based on the mesh, catalyst, and if present, the particulate support. In one embodiment of the invention, the mesh-like structure that is formed from a steam reforming catalyst and / or functions as a support for the steam reforming catalyst (the mesh-like structure preferably supports a catalytic steam reforming supported on a particulate support) is in the form of a packing structure configured to provide the turbulence of the gas phase flowing over the catalyst in the steam reformer tubes. The mesh structure can be provided with appropriate corrugations In order to provide increased turbulence, the mesh-like structure may include vortex tabs or generators to provide turbulence. The presence of turbulence generators allows mixing in the radial (and longitudinal) direction and allows improved heat transfer in the compared wall. with the processes known in the art This can be done by adding gener Turbulence Actors to the Structure Contacting the Wall For example, the structural packaging may be in the form of a module such as a roller of one or more sheets which is placed towards the reactor tubes so that the channels of the module follow the longitudinal direction of the tube The roll may consist of sheets that are corrugated or corrugated planar or a combination thereof and the sheets may contain fins or holes to promote mixing. The sheets may also be formed into corrugated strips that are separated from each other. of the other by a flat sheet that exactly fits the size of the tube and are held together by welding, wires, a flat cylindrical sheet or combinations thereof It should be understood that the mesh that is formed of a steam reforming catalyst or that supports the steam reforming catalyst (whose steam reforming catalyst may or may not be supported on a particulate support) can be used in a form other than a structured sheet. For example, the mesh can be formed as rings, particle slats etc. and employing in the tubes as a packed bed In one embodiment, the particle dimensions are smaller than those of packed bed particles known in the prior art. Thus the catalyst supported on the mesh (whether used or not as a structured packing is preferably used as a packed bed The steam reforming catalyst that is supported on the mesh-like structure may be present on the mesh-like support as a coating on the wires or fibers forming the mesh-like structure and / o may be present and retained in the interstices of the mesh-like structure In one embodiment, wherein the steam reforming catalyst supported on the particulate support is present as a coating on the mesh, the mesh may be initially coated with the particulate support, followed by the addition of the steam reforming catalyst to the particulate support Alternatively, the catalyst supported on a particulate support can be coated onto the mesh. The particulate support with or without catalyst can be coated on the mesh by a variety of techniques, eg, dipping or spraying. The supported catalyst particles can be applied to the mesh-like structure by contacting the mesh-like structure with a liquid coating composition (preferably in the form of a coating bath) that includes the dispersed particles in a liquid ba conditions such that the coating composition between or is formed into rovings towards the mesh-like structure and forms a porous coating on both the inner and outer portions of the mesh-like structure. Alternatively, the mesh-like structure is coated on a support in particles containing active catalyst or mesh-like structure can be coated with particles of a catalyst precursor. In a preferred embodiment, the liquid coating composition has a quinematic viscosity of not more than 175 centistokes and a surface tension no greater than 300 dynes / cm. In one embodiment, the supported catalyst or catalyst support is coated on the mesh by dip coating. In a preferred embodiment, the three-dimensional mesh-like material is oxidized before coating: e.g., heating in air at a temperature of 300 ° C. to 700 ° C. In some cases, if the mesh-like material is contaminated with organic material, the mesh-like material is cleaned prior to oxidation, for example, by washing with an organic solvent such as acetone. The coating bath is preferably a solvent system. mixing of organic solvents and water in which the particles are dispersed the polarity of the solvent system is preferably lower than that of the water in order to prevent the high solubility of the catalyst and obtain a suspension of good quality for coating. The solvent system can be a mixture of water amides esters and alcohols The kinematic viscosity of the coating bath is preferably less than 175 centistokes and the surface tension thereof is preferably less than 300 dmas / cm In a preferred embodiment of the invention the mesh-like structure which is coated includes metal wires or fibers and metal wires or fibers that are reve These are selected or treated in such a way that the surface tension thereof is greater than 50 dynes / cm as determined by the method described in "Advances in Chemistry 43 Contact Angle, Wettab lity and Adhesion American Chemical Soci? Tv 1964"By coating a mesh-like structure including metal fibers the liquid coating composition preferably has a surface tension of about 50 to 300 dmas / cm and more preferably about 50 at 150 dynes / cm as measured by the capillary tube method, as described in TC Patton's 'Paint Flow and Pigment Dispersion' 2nd Ed Wiley-Interscience 1979 page 223 At the same time the liquid coating composition has a no greater chemical viscosity 175 centistokes as measured by a capital viscometer and described in PC Hiemenz "Principles of colloid and Surface Chemistry" 2a d Marcel Dekker Inc 1986 p 182 In this modality the surface tension of the metal being coated is coorome with the viscosity and tension surface of the liquid coating composition so that the liquid coating composition is attracted to the interior d The structure to produce a particulate coating on the mesh-like structure The metal to be coated preferably has a surface tension that is greater than 50 days / cm and preferably TS higher than the surface tension of the coating composition. liquid to obtain spontaneous wetting and penetration of the liquid into the mesh In the case where the metal of the structure to be coated does not have the desired surface tension, the structure can be heat treated to produce the desired surface tension. Liquid coating can be prepared without any binders or adhesives to cause adhesion of the particulate coating to the structure The surface of the structure to be coated can also be chemically or physically modified to increase the attraction between the surface and the particles that form the coating, v gr heat treatment or chemical surface modification The solids content of the coating bath is generally from about 2% to about 50% preferably from about 5% to about 30% The bath may also contain additives such as dispersing surfactants , etc. In general, the weight ratio of additives to particles in the coating bath is from 0,0001 to 0 4 and more preferably from 0,001 to 0 1. The mesh-like material is preferably coated by immersing the mesh-like material in a coating bath one or more times as it dries and calcinates between dives The bath temperature is preferably room temperature, but it must be sufficiently below the boiling point of the liquid in the bath After coating the mesh-like material that includes a porous coating comprised of a plurality of particles is preferably dried with the material in a vertical position The drying is preferably achieved by contact with a flowing gas (such as air) at a temperature of 20 ° C to 150 ° C, more preferably 100 ° C to 150 ° C. After drying, the coated mesh-like material is preferably calcined, for example, at a temperature of 250 ° C to 800 ° C, preferably 300 ° C to 500 ° C more preferably to about 400 ° C. In a preferred embodiment, the temperature and air flow are coordinated in order to produce a drying regime that does not adversely affect the catalyst coating. v gr cracking pore blocking, etc. In many cases a slower drying rate is preferred The thickness of the formed coating can vary In general the thickness is at least 1 micron and in general not more than 100 microns Typically, the coating thickness does not exceeds 50 microns and more typically does not exceed 30 microns The inner portion of the mesh material that is coated has a porosity that is sufficient to allow the particles that comprise the coating to penetrate or migrate towards the three-dimensional network This way, the pore size of the three-dimensional material and the particle size of the particles comprising the coating in effect determine the amount and uniformity of the coating that can be deposited inside the network of material and / or the thickness of the coating on the The larger the larger pore sizes, the thickness of the coating that can be uniformly coated according to the invention. In the case when the particles are in the form of a catalyst precursor, the product, after depositing the particles, is treated to convert the catalyst precursor to an active catalyst. In the case where the particles that are deposited in the three-dimensional network of material is a catalyst support, the active catalyst or catalyst precursor can then be applied to said support, eg, by immersion spray, or impregnation. coating bath, the coating bath in some cases may include additives These additives change the physical characteristics of the coating bath, in particular the viscosity and surface tension so that during immersion, penetration of the mesh occurs and can be obtained a coating with a homogeneous distribution inside and outside the mesh The suns not only change the physical properties of the coating bath, but also act as binders After deposition, the article is dried and calcined As representative stabilizing agents can be mention: a polyacrylic acid similar to polymer, acrylamines, compue organic quaternary ammonium stools, or other special mixtures that are selected based on the particles. Alternatively, an organic solvent can be used for the same purpose. Examples of these solvents are liquid alcohols or paraffins. Controlling the pH of the suspension, for example, by adding HN03 is another method for changing the viscosity and surface tension of the coating suspension. In a preferred embodiment wherein the mesh is comprised of a plurality of layers of metal fibers, the particulate support with or without catalyst can be coated onto the mesh by an electrophoretic coating process, as described in the application of E.U.A. Serial Number 09 / 156,023, filed September 17, 1998. In said procedure, the wire mesh is employed as one of the electrodes, and the particulate support, such as an alumina support of the required particle size, with or without catalyst, (which preferably also includes alumina in the form of a sol to promote adhesion of larger particles to the wire mesh) is suspended in a coating bath. A potential is applied through the electrodes, one of which is the mesh formed of a plurality of fiber layers and the mesh is electrophoretically coated with the alumina support with or without catalyst. If the alumina support does not include a catalyst, A steam reforming catalyst, which is preferably comprised of nickel particles with or without one or more promoters is then added to the catalyst structure by dipping the structure (containing the alumina coating) into or impregnating the structure with a sulution solution. Suitable catalyst containing the nickel catalyst and preferably one or more promoters The Example illustrates the preparation of a catalyst by electrophoretic coating As indicated above, the steam reforming catalyst (with or without particulate support!) can be supported in the mesh material by trapping or retaining the catalyst in the interstices of the mesh. For example, when producing a therein comprised of a plurality of randomly oriented fiber layers a particulate support can be included in the mixture that is used to produce the mesh whereby the mesh is produced with the particulate support retained in the interstices of the mesh., said mesh can be produced as described in the aforementioned patents and with a 'jr ^ Mt ^? iááámá klt & alumina support that is added to the mesh containing the fibers and a binder, such as cellulose The mesh produced in this way includes the alumina particles retained in the mesh The particulate support retained in the mesh then is impregnated with nickel by methods known in the art The term "bed void volume" as used herein means the open space in the portion of the reaction zone eg the tubes of a steam reforming catalyst) it is not occupied by the mesh where the openings or pores in the mesh and the openings or pores in any catalyst or support in particles in the mesh is considered as being occupied by the mesh. In short, determining the "hollow volume of bed" the mesh is considered to be a closed ho and any catalyst and particulate support in the mesh is considered to be free of pores. The term "hollow volume of mesh hoist "means the total open space in the mesh and the open space in any particulate support and catalyst in the mesh." Percent of hollow volume of bed "is the ratio of the hollow volume of bed to the total volume of the portion of the reaction zone in which the mesh is placed multiplied by 100 The "hollow volume percent of mesh catalyst" is the ratio of open volume in the particulate support grid and catalyst divided by the total mesh volume, Particle and catalyst support (including pores or openings) multiplied by 100 The "hollow mesh volume percent" is the ratio of hollow volume in the mesh without catalyst or particulate support to the total volume of the mesh structure (openings and mesh material) multiplied by 100. The mesh-like structure used in the present invention (without catalyst and / or particulate support in the mesh) has a volume percent n mesh void which is at least 45% and is preferably at least 55% and more preferably at least 65% and still more preferably at least about 85% or 90% In general the void volume percentage of mesh does not exceed about 98% In general, the average hollow aperture is at least 10 microns and preferably at least 20 microns. The steam reforming reaction is usually carried out in a tubular furnace, often referred to as a steam reformer or a steam reformer furnace, the furnace of which includes a plurality of tubes that are heated appropriately in the furnace. In accordance with a preferred aspect of the present invention the mesh catalyst (in the form of a wire mesh which is the reforming catalyst of steam or in the form of a mesh that supports the steam reforming catalyst with or without a particulate support) is used in the reaction zone (for example, the tubes in the furnace) in a quantity ad so that the percent hollow volume of bed is at least 70% In most cases, the percent of hollow bed volume is not greater than 97% For example, in the case where the reforming catalyst of steam (with or without a particulate support) supported by the mesh is in the form of a packed bed the percent of hollow volume of bed is generally between 70% and 97% In the case where the steam reforming catalyst , with or without a particulate support, is supported on a mesh in the form of a structured packing, as opposed to a packed bed the bed is generally from 70% to 97% percent of hollow volume and in general the percent of The volume and void of the mesh catalyst is at least 50% preferably at least 60% and generally does not exceed 90%. In the case where the reform catalyst of A-feRc vapor is supported on the particulate support, the catalyst is generally present in the particulate support in an amount of 3 to 20% by weight, based on the catalyst and support in particles. Steam reforming is generally achieved at exit temperatures of at least 700SC, with the exit temperature in most cases not exceeding 900SC. The steam reforming inlet temperature is generally in the order of at least 500SC, and generally does not exceed 600SC The outlet pressure of the tubes containing the steam reforming catalyst is generally in the range of about 15 to 60 bar with the pressure drop across the tubes generally not exceeding 0.42 bar / meter of the tube length, and preferably not exceeding 0.31 bar / m. The steam reforming feed is generally comprised of a hydrocarbon (preferably methane) and steam, with the vapor to hydrocarbon ratios being at least 1 5, and usually not exceeding 6'1. The steam reforming reaction can be achieved in any of a wide variety of steam reforming furnaces, and can be combined with other processes, for example, a displacement reaction to increase the hydrogen content and to reduce the monoxide content In a separate mode, steam reforming takes place in multiple stages, where heat is generated in one of the stages used to provide or supplement the heat required for other stages. This can be done either in heated tubular reactors by hot gases or by using hot gases to preheat the feed to an adiabatic reactor. The present invention will be further described with respect to the following examples, however, it will be understood that the scope of the invention should not be limited by the same.

EXAMPLE 1 Small scale preparation of a steam reforming catalyst containing Ni on a wire mesh The 5 x 5 cm support is a metal mesh with a thickness of 0 8 mm of stainless steel fibers of 12 um in diameter and a 90% mesh void volume percent. The metal mesh is composed of a plurality of layers of metal fibers. The mesh is placed vertically in a bath containing a suspension. The aqueous suspension contains 10% by weight. of alumina catalyst support with a surface area of about 10 m2 / g or 11% by weight of Nyacol "" 20% alumina sol and 0.05% by weight of a commercial quaternary ammonium chloride agent The pH of the suspension was adjusted with HN03 diluted to 5 5 The mesh is connected to the negative pole of a power supply and placed between and parallel to two vertical metal electrodes that are connected to the positive pole of a power supply A potential of 5V is Apply duran 2 minutes during which the alumina is deposited towards the mesh. The sample is calcined in air at 500SC for 60 minutes. The amount of catalyst support that is deposited on the mesh is 25 1% by weight of the combined mesh and catalyst support. Coated wire mesh is impregnated to a point of incipient moisture with 1 10 g of an aqueous solution containing Ni (N03) 26H- > 0 to 20% The impregnated sample is heated in air at 525SC for 60 minutes to convert N? (N03) 2 into NiO After calcining the alumina in the support contains about 15% by weight of NiO EXAMPLE 2 Twenty percent of nickel oxide on calcium aluminate in suspension of distilled water is S? ^ s l & z & viX & dj ^ ^ * ^ ^ additionally milled in an Eiger Mili mill to obtain a suspension with an average particle size of < 3 microns One tenth of one percent of Stockhausen a dispersant, and 0 1 weight percent of 20% alumina sol (Nyacol "") in water were added and mixed well with a magnetic stirrer This suspension was further diluted with distilled water at 10 percent by weight for immersion coating Three monolithic structure packings (2 54 cm diam x 2 54 cm long) made with Inconel 600 fiber mesh material from US Filter Inc were washed with acetone and heat treated at 350 ° C for one hour Ceda structure was immersed in the prepared suspension, followed by removal of the excess suspension by a cannon and air air drying for 15 minutes and oven drying at 125aC for one hour, This operation was repeated four times The average weight gains after each dive were 6 1 11 4 16 1 21 1 and 24 7 weight percent, respectively. These coated monoliths were finally subjected to lime at 500SC for one hour before testing the reaction without gas The average catalyst load was 21 6% by weight EXAMPLE 3 g & # &s¡S s ^ & *. The same procedures were used for suspension and monolith preparation as in Examples 1 and 2. The dip coating processes were also the same except that two additional successive coatings were carried out for three monolith structures to achieve loading Upper Catalyst The weight gains after each immersion were 6 5, 12 2, 17.4, 22 3, 25 7, 29 1, and 31.8% by weight, respectively. The catalyst load was determined to be 28 2% by weight after calcining at 500aC for one hour. The present invention is particularly advantageous in that the mass transfer limitations in the catalyst are reduced by applying a thin coating of catalyst on the surface of a highly porous fibrous metal mesh. Accordingly, a volumetric activity that is superior to or similar to prior art processes can be obtained with a reduced amount of steam reforming catalyst. As a result of the high void volume of the catalyst bed and the mesh catalyst, it is possible to effect steam reforming at a lower pressure drop than in prior art processes., the present invention allows the reaction to be carried out with an improved thermal transfer in the wall, e.g., using the mesh as a structured packing, preferably with turbulence generators that make contact with the wall, or as a packed bed with smaller dimensions compared to those applied in processes known in the art, A particular heat flow, improved heat transfer by pressure drop and improved mass transfer allow the steam reforming process to be operated at a wall temperature lower that prolongs the life of the tube. The lower temperature reduces the formation of coke in the catalyst and consequently allows the use of lower vapor / carbon ratios (typically less than 3) than in prior art processes. This results in a reduction of downstream separation costs. Higher volumetric activity and improved heat transfer also allow superior heat flow through the wall, which is particularly useful if a high methane conversion is required. Numerous modifications and variations of the present invention are possible in light of the above techniques; therefore, within the scope of the appended claims, the invention can be practiced in another manner as is particularly described.

Claims (8)

1. - A process for producing a synthesis gas, comprising: reacting a hydrocarbon and vapor in a steam reforming reaction zone in the presence of a mesh selected from the group consisting of a mesh shape of a reforming catalyst steam and a mesh that supports a steam reforming catalyst

2. The process according to claim 1, wherein the mesh is a steam reforming catalyst and the reaction zone has a volume percentage of bed gap of at least 75% and not greater than 97%

3. The process according to claim 1, wherein the mesh is a mesh that supports a steam reforming catalyst and the steam reforming zone has a volume percentage of bed gap of at least 70% and the volume percentage of mesh catalyst gap is at least 50%.

4. The process according to claim 3, wherein the steam reforming catalyst is supported on a particulate support, and the particulate support is supported on the mesh

5. The process of compliance with the fe-isi-U-? fMii faith, * ¡ftü- ftft - > claim 4 wherein the catalyst and the particulate support are present on the mesh in an amount of at least 5% by weight 6 - The process according to claim 4, wherein the catalyst comprises at least one of nickel rhodium or ruthenium 7 - The process according to claim 6, wherein the mesh comprises a plurality of layers of metal fibers 8 - The process according to claim 7 wherein the supported catalyst is coated in the mesh 9 - The compliance process with claim 7 wherein the supported catalyst is trapped in the interstices of the mesh 10 - The process according to claim 4 wherein the combination of vapor reforming catalyst and particulate support is present in an amount of at least 5 % and not more than 60% by weight based on the catalyst, the particulate support and the mesh 11 - The process according to claim 1 0, wherein the pressure drop across the portion of the reaction zone containing the catalyst is not greater than 0 42 bar / m 12. The process according to claim 10, wherein the catalyst is present on the particulate support in an amount of 3% to 20%, by weight, based on the weight of the catalyst and particulate support. 13. The process according to claim 1, wherein the steam reforming catalyst is supported on a particulate support supported on the mesh. 14. The process according to claim 13 wherein the mesh is in the form of a structured packing, 15. The oroceso according to claim 13, wherein the average particle size of the support is less than 200 microns. 1

6. The process according to claim 15, wherein the average particle size of the support is not greater than 20 microns. 1

7. The process according to claim 15, wherein the mesh has a thickness of at least 5 microns and not greater than 2 mm and is comprised of a plurality of layers of metal fibers. 1

8. The process according to claim 17, wherein the reaction zone has a to ^ iis ^ Mi &? ^ i-volume percentage of bed gap at least 60% and not more than 97% 19 - The process according to claim 18 wherein the reaction zone is a reaction zone tubular 20 - a catalyst comprising a catalyst steam reforming supported on a mesh, the mesh comprising a plurality of layers of metal fibers metal fibers having a thickness of less than 30 microns 21 - the catalyst according to claim 20 wherein the catalyst steam reforming comprises active catalyst on a particulate support and the support is coated in the nick 22 - the catalyst according to claim 20 wherein the particulate support has an average particle size not greater of 20 microns^ J ^^ h ^ J ^