RU2286308C2 - Radial type device for production of the synthesis gas - Google Patents

Abstract

FIELD: chemical industry; devices for production of the synthesis gas.

SUBSTANCE: the invention is pertaining to the radial type device for realization of oxidation of the gaseous hydrocarbon fuels with the help of the catalytic agent and may be used for production of the synthesis gas. The radial type device for production synthesis gas contains the gas-distribution perforated tube 3 and the catalytic agent 4. The catalytic agent is made in the form of the annular heat-conducting dispensing catalytic plates and the heat-conducting separators with the grooves alternating among themselves with formation of channels for the gaseous streams running and connected among themselves. On the both sides of the separator 6 there are grooves 7 made in the form of the evolvent from the center to the periphery. The annular plates of the catalytic agent are mounted perpendicularly to the axis of the shafts of the gas-distribution perforated tube 3. Inside of the gas-distribution perforated tube 3 there is the starting system, which consists of the mixer 1 with the ignition plug 2 or the electric heating component. The invention presents the compact and effective device.

EFFECT: the invention presents the compact and effective radial type device used for realization of oxidation of the gaseous hydrocarbon fuels with the help of the catalytic agent and for production of the synthesis gas.

6 cl, 3 dwg

Description

The invention relates to a device for the partial oxidation of gaseous hydrocarbon fuels using an appropriate catalyst and can be used to produce synthesis gas and its further use in power plants using fuel cells and as additives to fuel in internal combustion engines, as well as in heating water heating systems to generate heat.

A device is known (see patent RU 2175799 dated 03/25/1997, "Installation of reforming for converting a reagent into reaction products (options) and a method for reforming", published in the bulletin of inventions No. 31, 2001), which can operate in partial mode oxidation of hydrocarbon gas. The device involves the use of a package in which there are sequentially located inert "heat-conducting plates" and catalytic plates, while the isothermality of the process is ensured by the good (radial) thermal conductivity of only the "heat-conducting plate" to ensure an isothermal mode of hydrocarbon gas oxidation. It is known that partial oxidation proceeds through the methane burning stage and subsequent reforming reactions; therefore, because of the high exothermicity of the combustion reaction, “hot spots” arise in the first part of the fixed catalyst bed, and therefore, the catalytic partial oxidation of methane is carried out in reactors at short contact times (fractions seconds) and thermal conductivity of the layer of at least 0.15 J / (sec · m · K) [M.Fathi, RHHofstad, T.Sperle, OARokstad, A.Holmen. Partial oxidation of methane to synthesis gas at very short contact times. // Catalysis Today 42, 1998, p.205-209]. The thickness of the catalytic layer provides a complete conversion of methane at a contact time of not more than 0.3 seconds. The temperature in the catalytic layer rises to 750-850 ° C. The most suitable material suitable for a long time under these conditions is an alloy of the composition Fe-Ni-Cr-Al or Fe-Cr-Al. Heat transfer from the surface of the catalytic layer to the external volume is carried out mainly by convection and infrared radiation; therefore, the occurrence of local “hot spots” on the catalytic plate is possible only by a significant increase in the thermal conductivity of the catalyst carrier, which allows the temperature to be redistributed over the cross section of the catalytic plate.

The disadvantage of this design is that the isothermal process is provided by the installation of inert "heat-conducting plates." These plates are the ballast mass in the structure, and with the thermal conductivity of the material of these plates less than 16 J / (sec · m · K), the plates must have a thickness several times greater than the thickness of the catalytic plates.

Known catalytic reactor (see patent RU 2208475 from 04/26/2001, published in the bulletin of inventions No. 20, 2003) for producing radial-type synthesis gas containing a gas distribution tube with a catalyst layer, which is made in the form of gas-permeable flat and corrugated reinforced tapes wound and sintered with a gas distribution pipe with gaps between the turns with the formation of gas-air channels between the tapes. The reactor has a heating device to put it into operation. The gas distribution pipe has perforation holes with a diameter smaller than the critical diameter to prevent flame from entering the gas distribution pipe. As a catalyst, a reinforced porous material containing active components is used: rhodium, nickel, platinum, palladium, iron, cobalt, rhenium, ruthenium, or a mixture thereof.

The above device is the closest in technical essence to the claimed device and therefore is selected as a prototype.

The disadvantage of this device is the lack of serial technologies mastered by the industry for the manufacture of reinforced porous materials, the high complexity and decrease in overall catalytic activity due to the use of reinforcing materials.

The technical problem to be solved is the creation of a compact radial type device for producing synthesis gas from hydrocarbon gas with increased efficiency.

The problem to be achieved is that the device for producing radial-type synthesis gas comprises a gas distribution perforated tube and a catalyst.

New is the implementation of the catalyst in the form of annular heat-conducting metal-porous catalytic plates and heat-conducting separators with grooves, alternating with each other with the formation of channels for the passage of gas flows and interconnected, while on both sides of the separator are made the grooves in the form of involute from the center to the periphery, while annular plates of the catalyst are mounted perpendicular to the axis of the gas distribution perforated tube. The heat-conducting separators are made of metal, the grooves in them are made by chemical etching using photolithography. The heat-conducting metal-porous catalytic plates are made by the method of porous rolling (see the book “Production of powder rolling” edited by Sorokin, Moscow, Metallurgy, 2002) or slip casting from heat-conducting metal powders, followed by the application of a porous substrate of magnesium oxide or aluminum oxide, or oxide zirconium and impregnation with catalytically active elements. Inside the gas distribution perforated tube there is a launch system, which consists of a mixer with a spark plug or an electric heating element.

Figure 1 presents the design of the claimed device.

Figure 2 presents a fragment of the catalytic block.

Figure 3 presents the design of the separator.

The device contains a sealed cylindrical body with located in it: a mixer 1, a glow plug 2 or an electric heating element, a gas distribution perforated tube 3 and a catalyst 4. The catalyst 4 (figure 2) is made in the form of a package of alternating annular heat-conducting metal-porous catalyst plates 5 and heat-conducting separators 6 installed perpendicular to the axis of the gas distribution perforated tube 3. In the separators 6 from the center to the periphery are made double-sided grooves 7 ( N grooves of width l, depth h), providing a radial passage of the reaction mixture. The grooves 7 in the separators are involute in length, belonging to the same radius of the main circle. To ensure uniform distribution of the mass flow along the grooves, the inlet section is narrowed to size t. The total depth of the grooves of the separator (on both sides) is up to 50% of the thickness of the separator S, the direction of the grooves on one side of the separator is made crosswise to the direction of the grooves on the other side of the separator. The dimensions of the catalytic unit (D is the outer diameter, d is the inner diameter and the number of catalytic plates) are determined by the required performance of the device. The grooves in the separators are made by milling or by chemical etching using photolithography. The separator material is Fe-Cr-Ni-Al alloy. From the input side of the reformed stream, the separator grooves are made of a smaller width (see element II of FIG. 3) in order to ensure uniform distribution of the mass flow both over the cross section and along the length of the catalytic unit. A package of catalytic plates and heat-conducting separators, to ensure thermal (thermal) contact, is pulled together by two rigid flanges, either with studs or with a nut through a gas distribution perforated tube 3. Metal-porous heat-conducting catalytic plates are made by the method of porous rolling or slip casting, porosity 40. ..70%, followed by the application of a porous substrate and impregnation with a catalytically active mass. As a catalyst, active components containing rhodium, nickel, platinum, palladium, iron, cobalt, rhenium, ruthenium, or a mixture thereof are used.

The material of metal-porous heat-conducting plates is Fe-Ni-Cr-Al or Fe-Cr-Al alloys with yttrium additives. The annular gap formed by the inner surface of the housing and the outer cylindrical surface of the catalytic package forms a reservoir for the extraction of synthesis gas. The uniform distribution of the reformed mixture along the length of the catalytic package is provided by a gas distribution perforated pipe 3, while the diameter of the perforation holes should be less than critical. Inside the gas distribution perforated tube 3 there is a gas start system, which consists of a mixer and a spark plug (glow or spark) or an electric heating element (TENA). The mixer is made in the form of a central tube with nozzle openings located normally on the outer surface of the hydrocarbon gas supply tube and an annular tube enclosing the central air supply tube, the air flow being twisted tangentially into the axis of the central tube. The nozzles for the supply of hydrocarbon gas are located uniformly both along the length of the central tube and along its generatrix, which ensures the homogeneity of the hydrocarbon gas-air mixture both at the stage of partial oxidation and at start-up (heating) - in the full oxidation mode. In this case, the pressure of the hydrocarbon gas should be slightly higher than the air pressure. The reactor is launched by heating the catalytic package to the temperature of the onset of the partial oxidation reaction. The heating of the catalytic package is carried out by heating the hydrocarbon gas oxidation products, while the ignition of the mixture of hydrocarbon gas-air is produced by a glow plug (incandescent or spark).

The design of the proposed catalytic reactor through the use of metalloporous heat-conducting catalytic carrier and a heat-conducting metal separator having good thermal conductivity, provides a mode close to isothermal. The nominal productivity of the catalytic reactor can be changed due to a set of catalyst layers and separators. The dimensions of the catalytic reactor are determined by the required performance, catalyst activity. The recommended thickness of the catalytic plates is 1-2 mm, the depth of the grooves of the separators is 0.4-0.6 mm, the width of the grooves of the separators is 3-15 mm.

The device operates as follows.

Initial reagents: hydrocarbon gas and air in the ratio α = 0.65-1 are supplied to the inlet port of the hydrocarbon gas and air, respectively. In the mixer 1, mixing of the gases takes place, and then the mixed stream enters the zone of the heated glow plug 2. The mixture ignites, and the catalytic unit is heated up with combustion products (flue gases). When the catalytic unit is heated to the temperature of the onset of partial oxidation (500-600 ° C), the ratio of hydrocarbon gas to air changes to α≈0.3-0.4. This mixture, passing through the catalytic unit, undergoes partial oxidation with the release of synthesis gas containing up to 33% hydrogen and up to 16-17% carbon monoxide when using natural gas as a hydrocarbon gas.

Claims (6)

1. A device for producing synthesis gas of a radial type, containing a gas distribution perforated tube and a catalyst, characterized in that the catalyst is made in the form of annular heat-conducting metal-porous catalyst plates and heat-conducting separators with grooves alternating with each other with the formation of channels for the passage of gas flows and interconnected by itself, while on both sides of the separator there are grooves in the form of an involute from the center to the periphery, ring catalyst plates are installed perpendi perpendicular to the axis of the gas distribution pipe. 2. The device according to claim 1, characterized in that the heat-conducting separators are made of metal. 3. The device according to claim 1, characterized in that the heat-conducting metal-porous catalytic plates are made by the method of porous rolling of heat-conducting metal powders, followed by the deposition of magnesium oxide and a catalytically active mass. 4. The device according to claim 1, characterized in that the grooves in the separator are made by chemical etching using photolithography. 5. The device according to claim 1, characterized in that a trigger system is located inside the gas distribution perforated tube. 6. The device according to claim 1, characterized in that the start-up system consists of a mixer with a spark plug or an electric heating element.

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