RU120092U1 - CATALYTIC SYNTHESIS GAS GENERATOR RADIAL TYPE - Google Patents

Abstract

1. A radial-type catalytic synthesis gas generator containing a mixer and a catalyst, characterized in that the catalyst is made in the form of a cylindrical gas-permeable unit, the generator contains a gas mixture flow distributor and a heat exchanger. ! 2. The device according to claim 1, characterized in that the catalyst can be made in the form of granules located between the outer surface of a smaller radius and the inner surface of a larger radius of cylinders with perforated walls. ! 3. The device according to claim 1, characterized in that it contains a gas mixture flow distributor located inside a gas-permeable cylindrical catalyst, which is a system of disks of different diameters fixed on a common axis, which ensures equalization of the inhomogeneity of the gas flow through the catalyst. ! 4. The device according to claim 1, characterized in that the heat exchange between the reaction products and the gases supplied to the catalyst can be carried out in the generator housing or separately in a remote heat exchange device. ! 5. The device according to claims 1-4, characterized in that the volumetric ratio of air: hydrocarbon gas when starting the generator is (8.0-10.0): 1, in the mode of generating synthesis gas - the volumetric ratio of air: hydrocarbon gas is (2.5-4.0): 1.

Description

The utility model relates to a device for processing hydrocarbon materials by partial oxidation to synthesis gas using an appropriate catalyst, and further use of a mixture of CO and H ₂ : in power plants using fuel cells; to create reducing atmospheres in the melting of metals; for further chemical processing into alcohols or synthetic liquid hydrocarbons.

A known method of producing synthesis gas during combustion and a device for its implementation (RF Patent No. 2320531, priority of 05/04/2006, published 03/27/2008) used the principle of homogeneous oxidation of hydrocarbons of the alkane series, in particular methane and / or mixtures thereof. The invention provides for the heating of the components of the mixture with the heat of the conversion gases. The disadvantage of the invention is that an external heat source is required, a continuous supply of flame to the reaction zone, as well as additional turbulators of the mixture and additional introduction of water vapor into the reaction zone to prevent soot formation, which complicates the design of the device. The maximum temperature in the reactor is 1450 K, which requires special heat-resistant structural materials.

Known (RF Patent 2374173, priority dated June 17, 2008, published November 27, 2009) is a synthesis gas generator based on a radiation burner, where a perforated three-dimensional ceramic matrix is used as a working element. The reaction mixture was supplied through the external walls of the matrix into the internal volume, i.e. “internal” heat recovery of the reaction occurred due to infrared radiation locked in the matrix walls. Oxidation of methane is carried out with an excess of the oxidizing agent α≥3.5 with the optimum for methane α = 0.25. The use of a perforated matrix allows to reduce the temperature of the matrix during the oxidation to 660-680 K, and the temperature of the products to 870-950 K. The main disadvantage of this invention is that a non-catalytic matrix is used and, accordingly, 1,4- 1.9% vol. Concentrations of CO and H _{2 are} low and make up 10.3-11.1% by volume, and hydrogen 17.8-22.1% calculated on dry gas.

The patent (RF Patent No. 2286308, priority dated January 31, 2005, published July 10, 2005) describes a radial type device for oxidizing gaseous hydrocarbon fuels using a catalyst and can be used to produce synthesis gas. A device for producing radial-type synthesis gas comprises a gas distribution perforated tube and a catalyst. 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. On both sides of the separator, grooves are made in the form of an involute from the center to the periphery. The annular plates of the catalyst are mounted perpendicular to the axis of the gas distribution perforated tube. Inside the gas distribution perforated tube there is a starting system, which consists of a mixer with a spark plug or an electric heating element. The device is compact and efficient. The device allows using air oxygen as an oxidizing agent to obtain a reaction mixture containing 33% hydrogen and up to 16-17% carbon monoxide, is operated at α≈0.3-0.4. The disadvantage of this device is the high complexity and multistage in manufacturing consisting in: the manufacture of metal-porous plates by rolling or slip casting, the application of a porous substrate from oxides of magnesium, aluminum or zirconium, and subsequent impregnation with catalytically active elements, the manufacture of separators similar in size to catalytic plates with subsequent manufacture grooves in separators by chemical etching using photolithography or milling. Assembly of elements of catalytic plates and separators on a gas distribution pipe with a high degree of compaction to ensure high thermal conductivity.

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

The objective of the invention is to increase the efficiency of synthesis gas generation, simplifying the design and operation of the device when operating in an autothermal mode. The specified technical result is achieved by the fact that a synthesis gas generator is used (Figure 1), consisting of a housing (1) with a catalytic gas-permeable block of cylindrical shape located inside the housing (2). A gas flow distributor (3) is located inside the catalytic block, which is a system of disks of different diameters fixed on the common axis, which ensures the smoothing of the inhomogeneity of the gas stream through the wall of the catalytic block. The gas flow distributor is attached to a gas-tight steel disk (4) located at the opposite end of the gas stream and cut off the catalytic block. The gas stream is fed along the axis of the catalytic block and moves radially through the walls of the cylindrical catalytic block, passing through the catalytic block, while the hydrocarbon gas is oxidized into synthesis gas. The reaction products due to convective heat transfer heat the air and hydrocarbon gas entering the conversion. The heat exchange device is located in the generator housing and is a tube (5) made of heat-resistant material located between the inner surface of the generator housing and the outer surface of the catalytic block. Or, the heat exchange device (6) (Figure 2) may be located outside the generator housing with the supply of reaction products through a heat-insulated pipeline (7). The generator is equipped with a mixer (8) and an ignition device (9). Heated air and hydrocarbon-containing gas passing through the heat exchanger (5) or (6) are supplied to the mixer, where they are mixed, after which the gas stream enters the catalytic unit.

The catalytic unit can also be made in the form of a gas-permeable cylinder and can be a monolithic product with gas channels obtained by self-propagating high-temperature synthesis (SHS), hydrothermal method or other method. The catalytic unit can be made in the form of two metal cylinders (Figure 3) from a heat-resistant alloy with perforated walls, and the granular catalyst (9) is placed between the outer surface of a small cylinder with an external radius r ₁ (10) and the inner surface of a large cylinder with an internal radius r ₂ (11). The geometric granule size L of the catalyst should be L≤ (r ₂ -r ₁ ) / 10. The upper section (4) is made of a gas-tight material, and with a diameter equal to the diameter of the large cylinder, and it is envisaged to mount the distribution device (3) (Figures 1, 2).

The device operates as follows: the initial reagents are hydrocarbon gas and air are supplied to the air inlet and hydrocarbon gas fittings, respectively, in air / hydrocarbon gas volume ratios = 8.0-10.0 / 1. The gas is mixed in the mixer, then the mixture enters the zone with a heated spark plug, the mixture ignites and the combustion products (flue gases) heat up the catalytic unit, when the catalytic unit is heated to a temperature (550-650 ° C), at which the partial oxidation reaction can proceed autothermal mode. After that, the air-hydrocarbon gas ratio changes to 4.0-2.5 / 1 volumetric (optimal for the synthesis gas generation). In the stationary mode of operation of the radial type synthesis gas generator (synthesis gas generation mode), heat is recovered through the use of heat exchangers, so the air and hydrocarbon gas supplied to the conversion are heated by convective heat transfer of the reaction products in the heat exchanger built into the generator body ( 5) or a remote heat exchanger (6). The heated gases are mixed into the mixers and the stream enters the catalytic unit, in a closed volume inside the catalytic unit, the gas-air mixture is additionally heated by infrared radiation emanating from the heated catalyst. Heat recovery during the process is necessary for the following reasons. The process of partial oxidation of hydrocarbons using methane as an example consists of several stages:

1. CH ₄ + O ₂ = CO ₂ + 2H ₂ O + 802 kJ / mol

2. CH ₄ + CO ₂ = 2CO + 2H ₂ -261 kJ / mol

3. CH ₄ + H ₂ O = CO + 3H ₂ -226 kJ / mol

4. 2CH ₄ + O ₂ = 2CO + 4H ₂ +70 kJ / mol

At the first stage, a part of methane is deeply oxidized to carbon dioxide and water with heat evolution (reaction 1), products of deep oxidation of carbon dioxide and water interact with residual methane to produce synthesis gas (reactions 2, 3) - these reactions proceed with heat absorption , the total process of partial oxidation of gas synthesis can be represented by equation 4, and it is characterized by a small heat release. To ensure the efficiency of the partial oxidation process and to maintain the heat balance of the generator and the complete conversion of methane, a heat recovery technique is used, which makes it possible to add additional energy to the catalytic process due to the heated gas-air mixture supplied to the catalyst.

Using the utility model is illustrated by the following examples:

Example 1. A synthesis gas generator is used with heat exchange tubes located inside the housing (Fig. 1). The catalyst obtained by SHS is used to synthesize the chemical composition of 50 wt% Ni and 50 wt% aluminum and magnesium oxides. The catalyst is a porous cylinder with an external diameter of 0.07 m, and a wall thickness of 0.025 m, a height of 0.09 m, the cylinder is closed at the end with a gas-tight steel disk with an external diameter of 0.07 m. Air is supplied in an amount of 25.8 l / min and hydrocarbon gas with a composition of 95.0% of methane, the rest is ethane, propane and butane; the flow rate of hydrocarbon gas is 3.0 l / min; the ratio of air / hydrocarbon gas = 8.6: 1. The ignition device is driven. After heating the catalytic unit with flue gases to a temperature of 600 ° C, the gas flow rate changes, which are 57.4 l / min for air and 20.5 l / min for hydrocarbon gas, air / hydrocarbon gas ratio = 2.8: 1. When stabilizing the temperature of the catalyst Tk = 845 ° C and the mixture of gases entering the catalyst Tg = 121 ° C, a synthesis gas with a CO content of 16.5% vol. And H ₂ 31.0% vol.

Example 2. A radial-type synthesis gas generator with a remote heat exchanger is used (Fig. 2). A catalyst is used similar to Example 1. The gas supply and start-up of the device are similar to Example 1. Air is supplied in an amount of 59.8 l / min and hydrocarbon gas 23.0 l / min, air / hydrocarbon gas ratio = 2.6: 1. The temperature of the mixture of gases entering the catalyst was Tg = 123 ° C, the temperature of the catalytic block was Tk = 814 ° C. The synthesis gas obtained in the generator contains CO - 16.4% vol., And H ₂ - 32.1% vol.

Example 3. A generator is used similar to example 1. The catalytic unit consists of a perforated inner cylinder with an external radius r ₁ = 0.011 m and a height of 0.11 m, and a perforated external cylinder with an internal radius r ₂ = 0.036 m with a height of 0.11 m. The cylinder assembly is closed by a steel disk with a radius of 0.04 m. Between the cylinders, a catalyst is filled with a particle size of 0.02-0.025 m, composition 15% of the mass of Ni, the rest is aluminum oxide and zirconium. The gas supply and start-up of the device is similar to example 1. Air is supplied in an amount of 55.4 l / min and hydrocarbon gas with a flow rate of 20.5 l / min, air / hydrocarbon gas ratio = 2.7: 1. The temperature of the mixture of gases entering the catalyst was Tg = 112 ° C, the temperature of the catalytic block was Tk = 800 ° C. The synthesis gas obtained in the generator contains CO - 16.8% vol., And H ₂ - 32.5% vol.

Example 4. A generator is used similar to example 2. The catalytic unit and the used catalyst are similar to example 3. Air is supplied with a flow rate of 38.0 l / min and hydrocarbon gas with a flow rate of 4.0 l / min, air / hydrocarbon gas ratio = 9.5 volume . The ignition device is driven. After heating the catalytic unit with flue gases to a temperature of 570 ° C, the gas flow rates change, which are 53.5 l / min for air and 17.8 l / min for hydrocarbon gas, air / hydrocarbon gas ratio = 3.0: 1. When stabilizing the temperature of the catalyst Tk = 854 ° C and a mixture of gases Tg = 138 ° C entering the catalyst, the synthesis gas at the outlet of the generator contains CO - 15.7% vol., And H ₂ - 30.1% vol.

As follows from the presented examples, the proposed technical solution ensures the achievement of the following technical result: generator efficiency, high concentrations of the resulting synthesis gas, ease of operation of the radial type synthesis gas generator, and control of the generator operating modes by changing the air and hydrocarbon gas flow rates.

Claims (5)

1. A radial-type synthesis gas catalytic generator comprising a mixer and a catalyst, characterized in that the catalyst is in the form of a cylindrical gas-permeable unit, the generator comprises a gas mixture flow distributor and a heat exchange device. 2. The device according to claim 1, characterized in that the catalyst can be made in the form of granules placed between the outer surface of the smaller radius and the inner surface of the larger radius of the cylinder with perforated walls. 3. The device according to claim 1, characterized in that it contains a gas mixture flow distributor located inside a gas-permeable cylindrical catalyst, which is a system of disks of different diameters mounted on a common axis, which ensures smoothing of the inhomogeneity of the gas stream through the catalyst. 4. The device according to claim 1, characterized in that the heat exchange between the reaction products and the gases fed to the catalyst can be carried out in the generator housing or separately in a remote heat exchange device. 5. The device according to claims 1 to 4, characterized in that the air: hydrocarbon gas volume ratio when the generator is started is (8.0-10.0): 1, in the synthesis gas generation mode, the air: hydrocarbon gas volume ratio is (2.5-4.0): 1.