RU154729U1 - ORGANIC FUEL FUEL CONVERTER FROM SINGLE TYPE CONVERSION ELEMENTS WITH HYDROGEN TAKING FROM REACTION ZONE - Google Patents

Abstract

A steam fossil fuel converter comprising a housing with a conversion system located inside, characterized in that the conversion system consists of a set of conversion elements having spacing ribs and made in the form of plates, the housing of which has a tube for removing hydrogen from the reaction zone and channels for supplying and discharging synthesis gas, while the flat conversion elements are aggregated into conversion sections, which are combined in conversion packages enclosed between crimping plates with feed pipelines Air cooling and strapped their hollow rods and plates conversion elements have cavities, with the first forward facing konversiruemyh fuel mixture conversion element installed in the cavity plate and the catalyst metal gasket, and in other plates conversion elements installed vodorodoprovodyaschaya catalyst and membrane.

Description

The utility model relates to the field of generation of pure hydrogen from fossil fuels and can be used in the chemical industry and in hydrogen energy. The main modern industrial method of hydrogen generation is the process of steam conversion of hydrocarbons, which consists in the decomposition of the feedstock in the presence of catalysts and at high temperature into a mixture of hydrogen, methane, carbon monoxide and carbon dioxide, followed by the release of pure hydrogen from a hydrogen-containing gas (see Arutyunov BC, Orlov O .V. Oxidative transformations of methane. - M.: Nauka, 1998). As the feedstock, both gaseous and liquid hydrocarbons can be used.

A known method of producing highly pure hydrogen (RF patent No. 2085476, C01B 3/32, 3/56, publ. 07.27.97), including sequential desulfurization of natural gas (GHG), mixing purified GHG with water vapor, steam conversion of the obtained gas-vapor mixture in a catalytic reactor to produce a mixture containing hydrogen and carbon monoxide, steam reforming carbon monoxide to form additional chemically free hydrogen, compressing the gas mixture, releasing carbon dioxide and water from it by freezing, and diffusing hydrogen through pall ievuyu membrane with separation of high purity hydrogen.

The disadvantages of this method are as follows:

- compression by the compressor of the gas mixture is provided at the final stages of the process, which requires energy costs for the compressor;

- hydrogen-containing gas after the separation of water and carbon dioxide by freezing has a low temperature. Diffusive evolution of hydrogen on a palladium membrane should occur at a temperature of from 773 to 900 K, which requires a supply of heat to heat the incoming gas and increases the cost of hydrogen production;

- the method does not provide for the utilization of heat of the exhaust flue gases, which can be used to heat the feed mixture fed to the steam reforming catalytic reactor, and to heat the air supplied to the combustion device, which leads to an increase in the specific fuel consumption per unit of produced products.

The disadvantages of this method are mainly due to the desire to obtain as much hydrogen as possible from the feedstock. Namely, low pressure increases the degree of conversion of hydrocarbons, and the separation of water and carbon dioxide contributes to a more complete release of hydrogen on the membrane. However, the combustible components of the synthesis gas remaining after the extraction of part of the hydrogen from it can be used in the combustion device to provide the conversion process with the necessary heat and, as a result, no chemical energy loss occurs. In addition, the production of additional hydrogen is associated with additional energy consumption, both in the form of heat and electric energy. Thus, despite the high yield of hydrogen from the feedstock, the energy conversion efficiency is low.

A known method of producing hydrogen from hydrocarbon gas (RF patent No. 2088517, C01B 3/32, 3/56, publ. 08.27.97).

In this method, steam conversion of a hydrocarbon gas is performed to produce a gas containing hydrogen and carbon monoxide. The resulting gas is fed to the conversion of carbon monoxide, then the converted gas is cooled to separate water condensate and carbon dioxide is released from the converted gas. Purification of the obtained hydrogen-containing gas from impurities is carried out by the method of short-cycle adsorption to produce hydrogen. The adsorbent is regenerated by purging part of the hydrogen produced to produce regeneration gases that are returned to the carbon monoxide conversion stage. The conversion stages are carried out at atmospheric pressure, and the adsorption stages are carried out at a pressure of from 1.5 to 3.0 MPa, for which the gas in front of the short-cycle adsorption apparatus is compressed using a compressor. Before applying to the steam conversion, condensation is carried out by hydrocarbon gas. This method has disadvantages:

- since the conversion stages of the process take place at atmospheric pressure, the metal consumption of the process equipment increases;

- at the final stages of the process, the gas mixture is compressed by a compressor from 1.5 to 3.0 MPa, which leads to an increase in the cost of equipment and maintenance;

- the allocation of carbon dioxide from the gas mixture is provided in a separate adsorber, which leads to an increase in the cost of installation;

- this method does not provide for the utilization of heat from the exhaust flue gases.

The most technically closest adopted as a prototype to the proposed utility model is the design of the installation for producing hydrogen from hydrocarbons according to the patent of the Russian Federation No. 2394754, C01B 3/34, C01B 3/12, publ. 07/20/2010. The installation comprises a hydrocarbon feed to the desulfurization unit, after which the hydrocarbon gas purified from sulfur compounds is divided into two streams. One gas stream is mixed with water vapor and subjected to steam reforming in a steam reforming catalytic reactor at a temperature of 800-1050 ° C. The obtained converted gas is fed as a heating medium to a steam recovery boiler, the gas cooled therein is sent to a catalytic reactor for steam conversion of carbon monoxide at a temperature of 190-220 ° C, then the resulting hydrogen-containing gas is additionally cooled to a temperature of 20-40 ° C by an external refrigerant and is separated from moisture in a gas cooler-dryer, after which it is fed to a hydrogen-containing gas separation unit in which hydrogen is released by short-cycle adsorption. Purge gas is diverted from the separation unit and mixed with a second stream of sulfur-free hydrocarbon gas, the resulting mixture is fed as fuel gas to the burner of a catalytic steam reforming hydrocarbon reactor, before being fed to the burner, this mixture and the air required for combustion are heated in a heat recovery unit, after whereby the flue gases to separate the moisture are additionally cooled by an external coolant in the flue gas cooler-dryer and are taken out of the installation to the atmosphere.

The disadvantages of this prototype are:

- Carrying out the conversion of hydrocarbons at high temperature, leading to the need to use expensive structural materials;

- the presence of significant heat losses, compensated by the supply to the combustion of not only purge gas, but also an additional amount of hydrocarbon fuel;

- low compact design.

The objective of the proposed utility model is to create a compact design of a steam converter of organic fuel, which allows to ensure high energy efficiency of its application and reduce the cost of its production.

The technical result of the utility model is, firstly, a decrease in the amount of steam required for the conversion, which reduces the specific energy consumption in the production of hydrogen, and secondly, a decrease in temperature in the conversion zone, which eliminates the use of heat-resistant alloys and uses cheaper structural materials thirdly, the high compactness of the design, which reduces its cost and expands the scope of use.

The technical result is achieved due to the fact that the conversion system is made in the form of a set of the same type of conversion elements having the form of plates having cavities with a catalyst and a hydrogen-conducting membrane in them, in which the conversion takes place while hydrogen is taken from the reaction zone, flat conversion elements are aggregated in conversion sections, conversion sections are combined into conversion packages enclosed between crimping plates and pulled together by hollow rods, conversion elements The entrances included in the conversion sections have spacing ribs and in the first conversion element in the direction of the converted fuel mixture, instead of a hydrogen-conducting membrane, its simulator is a metal gasket, and for cooling the crimp plates, their outer walls are blown with air.

The advantages of generating hydrogen while removing hydrogen from the reaction zone through hydrogen-conducting membranes are known. Due to the continuous removal of hydrogen from the reaction zone, the conversion proceeds freely, without restrictions on chemical equilibrium, so that the working temperature in the conversion zone can be reduced to values of 550-600 ° C, which can dramatically increase the converter resource and use an order of magnitude cheaper construction materials. In addition, it becomes possible to carry out steam conversion with a minimum excess of steam in relation to the stoichiometric ratio, which reduces the energy costs of the conversion and leads to an increase in the efficiency of the converter up to 75 ... 80%. The conversion elements are in the form of flat plates, allowing you to develop both a catalyst surface and a surface for supplying thermal energy for the occurrence of an endothermic reaction. The conversion elements can be aggregated into flat conversion sections, the conversion sections are combined into conversion section packets, and the conversion section packets are combined into a conversion system enclosed between crimping plates pulled together by rods. The latter provides the possibility of creating a sufficiently high pressure of the conversion medium inside the plate elements with very thin walls of the conversion elements, which provide good heat transfer and, accordingly, high dynamic characteristics of the process. The number of conversion elements in a section, the number of conversion sections in a batch, and the number of packets in a conversion system can vary widely while maintaining the total number of conversion elements and can be sufficient to provide the necessary hydrogen converter performance. This makes it possible to flexibly change the overall dimensions of the converter, which can be especially important in the presence of severe restrictions on the overall dimensions. The modularity of the design allows the creation of converters with a wide range of hydrogen performance based on the same type of conversion elements.

The design of the utility model and its operation is illustrated by the following specific example of its implementation, shown in the illustrations of FIG. 1, FIG. 2, FIG. 3, FIG. 4 and FIG. 5.

The following elements are indicated in the illustrations:

1 - Conversion section;

2 - Conversion element;

3 - housing conversion element;

4 - Cover;

5 - distance ribs;

6 - hydrogen discharge tube;

7 - Prefabricated hydrogen collector;

8 - Channel for supplying synthesis gas;

9 - Channel removal of synthesis gas;

10 - Crimp plates;

11 - Hollow rods;

12 - catalyst;

13 - Palladium membrane;

14 - Air supply pipe for cooling crimp plates;

15 - Air supply pipe for cooling hollow rods;

16 - Air exhaust pipe after cooling the crimp plates;

17 - Metal gasket;

18 - Converter housing;

19 - Conversion system.

In this example, the conversion system contains one conversion package of eight conversion sections 1, each of which combines four conversion elements 2 (Fig. 3). The housing of the conversion element 3 is a steel disk in which a cylindrical cavity is machined to accommodate the internal contents of the catalyst 12 and the water-conducting palladium membrane 13 (Fig. 4) or a metal strip 17 (Fig. 5). The cavity is closed by a cover 4 welded to the body, having spacing ribs 5 on the outside (Fig. 4). On the cylindrical part of the housing surface, a hole is drilled into the cavity through which the outlet pipe 6 is discharged, providing production hydrogen to the collection manifold 7. On the opposite side of the element, channels are drilled on the cylindrical surface of the housing to supply synthesis gas 8 through the feed channel to the conversion element the synthesis gas from the previous conversion element of the section and the removal of synthesis gas from it through the exhaust channel 9 to the next element of the section after passing through the reaction zone of this element. Hydrogen-depleted synthesis gas remaining after the passage of the last conversion element 2 is sent to the combustion device (not shown in FIG.), And the heat released as a result of its combustion ensures the maintenance of the conversion reaction.

The conversion sections 1 are placed inside the housing of the converter 18 close to each other, while the spacing ribs 5 provide a fixed channel width between the sections. In operating conditions, flue gas passes through these channels, transferring the heat necessary for the conversion. The whole package of conversion sections is between two compression plates 10. The plates are pulled together by hollow rods 11. The compression plates 10 on the inside and the compression rods from the outside are also heated by flue gas, but unlike conversion sections in which heat is consumed during the reaction , they must be forced to cool in order to have the same temperature level as that of the conversion sections. For this purpose, the crimp plates 10 are on the outside, and the hollow rods 11 are internally blown with air (air is supplied through pipelines 14 and 15, respectively, in FIG. 1), which is then fed (for example, after cooling of the crimp plates through piping 16) to the furnace device providing a combustion process in it.

Due to this measure, thermal stresses in the structural elements of the converter are minimized and, accordingly, its reliability and service life are increased. In operating modes, a steam-gas mixture is fed to the input of the conversion system, which is evenly distributed (due to the equal hydraulic resistance of the paths) to the conversion sections. Since the pressure of production hydrogen is established during operation to be almost the same inside all conversion elements, and in the first, during the movement of the mixture, the conversion elements of the sections, the partial pressure of hydrogen at the inlet of the reaction zone is zero, to prevent diffusion of production hydrogen into the reaction mixture, in each of sections in the first in the direction of the mixture of the conversion element, hydrogen is not removed. In this conversion element, instead of the palladium membrane 13 (Fig. 4), its simulator is installed - a metal gasket 17 (Fig. 5) and there is no hydrogen removal tube 6 in the case of the conversion element 6. The synthesis gas leaving the first conversion element subsequently passes through the rest section conversion elements, now already delivering hydrogen through the membrane 13.

The calculations showed that for this converter with the operating parameters provided for it (temperature in the reaction zone 600 ° C, pressure 15 kgf / cm ² abs.), The steady-state hydrogen yield will be 340 g per 1 kg of natural gas, which corresponds to energy efficiency 81.6%. When using similar converters for the conversion of liquid hydrocarbons, the energy efficiency is slightly lower, falling in the range of 75 ... 80%. It should also be noted that during the conversion of liquid hydrocarbons, a pre-reforming stage of the steam-fuel mixture is necessary to exclude the possibility of a rapid deterioration of the converter characteristics during operation due to the tendency of higher hydrocarbons to tar and soot formation on the catalyst surface.

Claims (1)

A steam organic fuel converter comprising a housing with a conversion system located inside, characterized in that the conversion system consists of a set of conversion elements having spacing ribs and made in the form of plates, the housing of which has a tube for removing hydrogen from the reaction zone and channels for supplying and discharging synthesis gas, while the flat conversion elements are aggregated into conversion sections, which are combined in conversion packages enclosed between crimping plates with feed pipelines Air cooling and strapped their hollow rods and plates conversion elements have cavities, with the first forward facing konversiruemyh fuel mixture conversion element installed in the cavity plate and the catalyst metal gasket, and in other plates conversion elements installed vodorodoprovodyaschaya catalyst and membrane.

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