CN201400568Y - A palladium membrane hydrogen separation device based on high temperature preheating - Google Patents

Abstract

The utility model discloses a palladium membrane hydrogen separation device based on high-temperature preheating. There is a syngas circulation frame between it and the palladium membrane module. The syngas circulation frame is a square frame with a cavity in the middle; the square frame forms a closed space with the blind flange or the palladium membrane module, and there are Bosses, high-temperature gas inlet pipes, outlet pipes, and high-temperature gas circulation channels; the channel cross-section of the high-temperature gas circulation channel is circular with a diameter of 3-5 mm, or the channel cross-section of the high-temperature gas circulation channel is rectangular, The side length is 3-5 mm. The utility model introduces high-temperature flue gas into the gas circulation channel of the syngas frame to preheat and constant-temperature membrane separator, has fast heating rate and good temperature control effect, and is especially suitable for combined use with devices with high-temperature tail gas discharge to improve energy utilization efficiency.

Description

A palladium membrane hydrogen separation device based on high temperature preheating

technical field

The utility model relates to a membrane separation device for separating and producing high-purity hydrogen from hydrogen-containing synthesis gas, in particular to a membrane separation device which adopts high-temperature gas preheating, constant temperature, easy heating and good temperature control effect. The device can produce high-purity hydrogen from hydrogen-containing mixed gas.

technical background

At present, 90% of the hydrogen in the world comes from the reforming of hydrocarbons (natural gas, coal, biomass, etc.), purification after chemical processes such as gasification or cracking, and the purification of synthesis gas is one of the key processes. Available purification techniques include: pressure swing adsorption, polymer membrane separation, palladium membrane separation, low temperature separation, etc. Compared with other separation technologies, palladium membrane separation can produce high-purity hydrogen containing only ppb-level impurities, which is especially suitable for fuel cells; in addition, the palladium membrane separation device occupies a small area and is easier to miniaturize than other separation methods .

The transfer of hydrogen in the palladium membrane obeys the so-called "solution-diffusion" (Solution-diffusion) mechanism, which includes the following processes: hydrogen diffuses from the boundary layer to the surface of the palladium membrane; hydrogen decomposes into hydrogen atoms on the membrane surface; Atoms are dissolved by the palladium membrane; hydrogen atoms diffuse from the high pressure side to the low pressure side in the palladium membrane; hydrogen atoms recombine into hydrogen molecules on the low pressure side of the palladium membrane; hydrogen gas diffuses away from the membrane surface. According to the above theory, the penetration rate of hydrogen in the palladium membrane is related to the temperature, thickness, alloy composition of the membrane, and the partial pressure of hydrogen on both sides of the membrane, and can be expressed by Sieverts'Law:

$\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; k</span>}\frac{\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;E</span>}}{\mathrm{<span\; class="notranslate">\; RT</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}}^{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span>$

In the formula:

R: Gas constant; T: Temperature; A: Membrane area; L _: Membrane thickness; _E : Activation energy; Coefficient before function; M: transmittance.

The production of hydrogen by palladium membrane separation needs to be carried out at the working temperature of the palladium membrane. There are several ways to raise the temperature of the palladium membrane separator. Using electric heating or thermal fluid heating, this method has a faster heating rate and can perform good temperature control, but it is difficult to process micro-scale channels on palladium membrane components. In addition, in order to prevent the temperature loss of the palladium membrane module, heat insulating materials, such as ceramics, can be placed outside the palladium membrane module. The membrane separator can be heated through its auxiliary components. This heating method is relatively simple to process and convenient to apply.

Chinese invention patent application "a membrane separation device for producing high-purity hydrogen" (application number: 200810199114.8) discloses a membrane separation device for producing high-purity hydrogen, including a palladium membrane module, a syngas circulation frame, a blind flange, Graphite gasket, connecting bolts and nuts; multiple palladium membrane modules are arranged between two blind flanges, and syngas circulation is arranged between blind flanges and palladium membrane modules and between palladium membrane modules and palladium membrane modules Graphite gaskets are installed between the frame, the blind flange and the syngas circulation frame and between the syngas circulation frame and the palladium membrane module; the syngas circulation frame is a square frame with a cavity in the middle; the square frame and the blind flange or The palladium membrane module forms a closed space, and the synthesis gas circulation frame is provided with hydrogen-containing synthesis gas import and export pipes, and the import and export pipes communicate with the gas circulation space of the palladium membrane module; bosses are provided around the synthesis gas circulation frame. However, the preheating or constant temperature of the device needs to be realized by the heat of the high-temperature inert gas flowing through the synthesis gas circulation frame or the high-temperature hydrogen-containing synthesis gas itself.

Chinese invention patent application "a membrane separation device for producing high-purity hydrogen with electric preheating and constant temperature" (application number: 200810218798.1) discloses a membrane separation device for producing high-purity hydrogen by electric heating. A plurality of palladium membrane modules are arranged between the flanges, a synthesizer flow frame is arranged between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module, and a synthesizer circulation frame is arranged between the blind flange and the syngas flow frame Graphite gaskets are installed between the syngas circulation frame and the blind flange; the syngas circulation frame is a square frame with a cavity in the middle; the square frame and the blind flange or palladium membrane module form a closed space, The frame is provided with hydrogen-containing synthesis gas import and export pipes; bosses are provided around the synthesis gas circulation frame, grooves are provided on the four walls, electric heating wires are provided in the grooves, and insulating materials are provided outside the electric heating wires. The device uses electric heating to preheat or constant temperature membrane separator, which is suitable for laboratory scale and practical. For large-scale industrial use, it is relatively wasteful to use the highest quality electrical energy to heat or thermostatic membrane separators. Industrial-scale hydrogen production processes generally generate high-temperature flue gas, and using high-temperature flue gas to preheat or a constant temperature membrane separator is a feasible option.

Utility model content

The utility model aims at the hydrogen-containing synthesis gas produced in the chemical industry, uses the palladium membrane assembly as the main component, and uses the high-temperature gas heating as the main heating method to provide a palladium membrane separation suitable for preheating the high-temperature flue gas and maintaining a constant temperature devices to improve energy efficiency.

Main implementation scheme of the present utility model is as follows:

A palladium membrane hydrogen separation device based on high temperature preheating, a plurality of palladium membrane modules are arranged between two blind flanges, and a palladium membrane module is arranged between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module. There is a syngas circulation frame, and graphite gaskets are installed between the blind flange and the syngas circulation frame and between the syngas circulation frame and the palladium membrane module; the blind flange is a square plate; the blind flange and the palladium Grooves are respectively provided around the side where the membrane module is connected to the synthesis gas circulation frame, and graphite gaskets are provided in the grooves, and the boss of the synthesis gas circulation frame is sealed and connected with the blind flange and the groove on the palladium membrane module; The synthesis gas circulation frame is a square frame with a cavity in the middle; the square frame forms a closed space with the blind flange or palladium membrane module, and the synthesis gas circulation frame is provided with hydrogen-containing synthesis gas import and export pipes, and the import and export pipes are connected with the The cavities in the synthetic gas circulation frame of the palladium membrane module are connected; the syngas circulation frame is provided with bosses, high-temperature gas inlet pipes, outlet pipes and high-temperature gas circulation channels; the channel cross-section of the high-temperature gas circulation channels is a circle shape, the diameter of which is 3-5 mm, or the channel cross-section of the high-temperature gas circulation channel is rectangular, and the side length is 3-5 mm.

In order to further realize the purpose of the utility model, there are porous sintered metal supports and palladium alloy membranes on both sides of the membrane support frame of the palladium membrane module, and the membrane support frame contains a purified hydrogen gas flow passage, which is two symmetrical rectangles Toothed combination, channel width is 3-5 mm, the support frame between the channels is 3-5 mm, the gas outlet is set at the upper and lower ends of the support frame, and communicates with the air flow channel; the surrounding of the membrane support frame is processed one Rectangular groove for sealing with syngas circulation frame, said groove is 3-7 mm wide and 1-3 mm deep.

Round holes are opened around the blind flange for fixing with bolts during assembly.

The sides of the blind flange and the palladium membrane assembly connected to the synthesis gas circulation frame are respectively provided with rectangular grooves, the width of which is 3-7 mm, and the depth is 1-3 mm.

The width of the boss of the synthesis gas circulation frame is 0.3-0.7 mm narrower than the width of the groove of the blind flange and the palladium membrane assembly, and the height is the same as the depth of the groove of the blind flange and the palladium membrane assembly.

The graphite gasket is a rectangular gasket made of high temperature resistant graphite, the width is the same as that of the blind flange and the groove of the palladium membrane assembly, and the thickness is 0.3-0.5 mm.

After the palladium membrane separator is assembled, it is covered with thermal insulation material to reduce heat loss. The insulation material is made of high-temperature-resistant ceramic fiber or other materials, and the thickness of the material is calculated to ensure that the temperature of the outer surface of the insulation material is not higher than the ambient temperature by 10°C.

In the utility model, the separator is heated by high-temperature gas, the heating rate is fast, and the temperature is easy to control, which is especially suitable for applications with high-temperature tail gas discharge.

Description of drawings

Figure 1 is an assembly diagram of a membrane separation device for producing high-purity hydrogen.

FIG. 2 is a partially enlarged view of FIG. 1 .

Fig. 3 is a half-sectional view of a palladium membrane module.

Fig. 4 is a sectional view of the palladium membrane module A-A in Fig. 3 .

Fig. 5 is a B-B sectional view of the palladium membrane module in Fig. 3 .

Figure 6-1 is the right view of the syngas circulation frame.

Figure 6-2 is a D-D sectional view of the syngas circulation frame in Figure 6-1.

Figure 6-3 is a sectional view of the syngas circulation frame C-C in Figure 6-2.

Figure 7-1 is a schematic diagram of the blind flange structure.

Figure 7-2 is the E-E sectional view of the blind flange structure in Figure 7-1.

Detailed ways

Below in conjunction with accompanying drawing and specific example the utility model is described further. It should be noted that the examples cited are only used to further illustrate the technical features of the utility model, rather than to limit the utility model.

As shown in Figures 1 and 2, a palladium membrane hydrogen separation device based on high-temperature preheating includes a palladium membrane module 1, a synthesis gas circulation frame 2, a blind flange 3, a graphite gasket 4, bolts and nuts 5, and high-temperature gas Circulation channel 204 . A plurality of palladium membrane modules 1 are arranged between two blind flanges 3, and a synthetic gas circulation frame 2 is arranged between the blind flanges 3 and the palladium membrane modules 1 and between the palladium membrane module and the palladium membrane module. The gas circulation frame 2 separates the two, and to maintain sealing, graphite gaskets are installed between the blind flange and the syngas circulation frame and between the syngas circulation frame and the palladium membrane module. The number of palladium membrane modules can be determined according to the required hydrogen production, the operating conditions of the separator (temperature, pressure, etc.), the area and thickness of the palladium membrane and other geometric dimensions. If the number of palladium membrane modules required by the whole device is N, the number of syngas circulation frames required is N+1, the number of graphite gaskets is 2N+2, and the number of blind flanges is 2. In order to heat the membrane separator, high temperature gas is introduced into the high temperature gas circulation channel 204 around the syngas circulation frame. The syngas circulation frame, the palladium membrane module, and the blind flange are fixed by connecting bolts and nuts 5 .

As shown in FIGS. 3 to 5 , the palladium membrane module 1 includes a membrane support frame 101 , a porous sintered metal support body 105 , a palladium alloy membrane 106 and a hydrogen outlet tube 104 . There are porous sintered metal supports 105 and palladium alloy membranes 106 on both sides of the membrane support frame 101. The membrane support frame 101 contains a purified hydrogen gas flow passage 102, which is a combination of two symmetrical rectangular teeth with a width of 3- 5 mm, preferably 4 mm, the support frame between the channels is 3-5 mm, preferably 4 mm, the gas outlet 104 is arranged at the upper and lower ends of the support frame 101, and communicates with the air flow channel 102. The support frame 101 is made of stainless steel, and the porous sintered metal support body 105 is made of sintered stainless steel. The supporting frame is connected to the sintered metal by welding. The palladium alloy film 106 is a palladium-silver alloy film with a thickness of 10-50 microns, and a 25-micron palladium-silver alloy film is used here. The palladium alloy film 106 is sealed and connected with the metal support frame 101 and the porous sintered metal support body 105 by metal diffusion. The molecules of the frame 101 diffuse with each other, so as to achieve the effect of sealing. Groove 103 is processed around the membrane support frame 101, with a width of 3-7 millimeters, preferably 5 millimeters, and a depth of 1-3 millimeters, preferably 1 millimeter; when assembling, add graphite with a thickness of 0.4 millimeters and a width of 5 millimeters in the groove 103 The gasket 4 is docked with the boss 203 of the synthesis gas circulation frame 2 ( FIG. 2 ).

As shown in Figures 6-1, 6-2, and 6-3, the synthesis gas circulation frame 2 is a stainless steel square frame with a cavity in the middle and a rectangular groove on the four walls. After installation, a closed space 201 is formed with the blind flanges and palladium membrane modules on both sides, and the synthesis gas can flow in this space. Hydrogen-containing synthesis gas inlet and outlet pipes 202 are welded at both ends of the synthesis gas circulation frame 2 , and the introduction and outlet pipes 202 communicate with the gas circulation space 201 . A boss 203 with a width of 4.5 mm and a height of 1 mm is processed on both sides of the frame for sealing when the synthesis gas circulation frame 2 is combined with the palladium membrane module 1 or the blind flange 3 ( FIG. 2 ). A high-temperature gas circulation channel 204 with a circular cross-section is processed around the synthesis gas circulation frame 2 for preheating and constant temperature of the membrane separator, and its diameter is 3-5 mm, preferably 5 mm. The channel cross-section of the high-temperature gas circulation channel 204 can also be rectangular, and the side length can be 3-5 mm. The setting of the high-temperature gas circulation channel 204 facilitates the use of high-temperature gas for heating, the heating rate is fast, and the temperature is easy to control, which is especially suitable for applications with high-temperature exhaust gas emissions.

As shown in Figures 7-1 and 7-2, the blind flange 3 is a square stainless steel plate 301 with a thickness of 15 mm. Hole 303 is opened on the periphery of blind plate flange, and bolt 5 is fixed (Fig. 1) when being used for assembling. On the side where the blind flange 3 is connected with the synthetic gas circulation frame 2, the processing width is 5 mm, and the depth is a rectangular groove 302 of 1 mm; The graphite gasket 4 of 5 mm is sealed with the boss 203 of the syngas circulation frame 2 again.

The graphite gasket 4 is a rectangular gasket made of high temperature resistant graphite. The gasket is 5 mm wide and 0.3-0.5 mm thick, preferably 0.4 mm.

The suitable working temperature of the palladium membrane is 450-600°C. After the palladium membrane separator is assembled, it is covered with thermal insulation material to reduce heat loss. The heat-insulating material can be made of high-temperature-resistant ceramic fiber or other materials, and the thickness of the material is calculated to ensure that the temperature of the outer surface of the heat-insulating material is not higher than the ambient temperature by 10°C.

As shown in Figures 1 and 2, the assembly sequence of a palladium membrane separation device containing two palladium membrane modules is: blind flange, graphite gasket, synthesis gas circulation frame, graphite gasket, palladium membrane module, graphite gasket, Syngas circulation frame, graphite gasket, palladium membrane module, graphite gasket, synthesis gas circulation frame, graphite gasket, blind flange; the parts of the whole device are fixed by connecting bolts and nuts. When it is necessary to increase the number of palladium membrane modules, graphite gaskets, syngas circulation frames, and palladium membrane modules can be added sequentially in the blind flange.

When working, first use the high-temperature gas channel 204 to preheat the membrane separator. When the temperature rises to the working temperature of the palladium membrane (generally at 450-600°C), the high-pressure hydrogen-containing mixed gas flows through the frame 2 through the synthesis gas. In the hydrogen-containing gas circulation channel, the hydrogen in the mixed gas is in contact with the palladium membrane 106, and is transferred to the hydrogen gas circulation channel 102 through the palladium membrane 106 and sintered metal 105, and then the palladium membrane is separated from the hydrogen gas outlet tube 104. device to become high-purity product hydrogen. In the constant temperature stage of the membrane separator, it is realized by reducing the flow rate of high temperature gas or mixing in normal temperature air.

In the usual membrane separator heating method, high-temperature inert gas is generally used or the inside of the palladium membrane module is processed into a scale channel. Due to the high cost of preparing high-temperature inert gas, there are still some problems in processing micro-scale channels on the palladium membrane module. Difficulties. The utility model is expected to make full use of a large amount of heat in the high-temperature exhaust gas, process circular or rectangular circulation channels around the syngas circulation frame to preheat the membrane separator and maintain a constant temperature, and is especially suitable for joint use with devices with high-temperature exhaust gas discharge , Improve energy efficiency.

Claims (6)

1. A palladium membrane hydrogen separation device based on high-temperature preheating. Multiple palladium membrane modules are arranged between two blind flanges, between the blind flange and the palladium membrane module, and between the palladium membrane module and the palladium membrane module. There is a syngas circulation frame between them, and graphite gaskets are installed between the blind flange and the syngas circulation frame and between the syngas circulation frame and the palladium membrane module; the blind flange is a square plate; There are grooves around the side where the palladium membrane module is connected to the synthesis gas circulation frame, and graphite gaskets are arranged in the grooves, and the boss of the synthesis gas circulation frame is sealed and connected with the blind flange and the groove on the palladium membrane module; It is characterized in that: the synthesis gas circulation frame is a square frame with a cavity in the middle; the square frame forms a closed space with the blind flange or the palladium membrane module, and the synthesis gas circulation frame is provided with hydrogen-containing synthesis gas import and export pipes , the import and export pipes communicate with the cavities in the syngas circulation frame of the palladium membrane module; bosses, high-temperature gas introduction pipes, outlet pipes and high-temperature gas circulation channels are arranged around the syngas circulation frame; the high-temperature gas circulation channels The channel cross-section is circular with a diameter of 3-5 mm, or the channel cross-section of the high-temperature gas circulation channel is rectangular with a side length of 3-5 mm. 2. The palladium membrane hydrogen separation device based on high temperature preheating according to claim 1, characterized in that: there are porous sintered metal supports and palladium alloy membranes on both sides of the membrane support frame of the palladium membrane module, and the membrane support frame It contains the purified hydrogen gas flow passage, which is a combination of two symmetrical rectangular teeth, the width of the passage is 3-5mm, the support frame between the passages is 3-5mm, and the gas outlet is set at the upper and lower ends of the support frame , communicated with the air flow channel; a rectangular groove for sealing with the synthetic gas circulation frame is processed around the membrane supporting frame, the groove is 3-7 mm wide and 1-3 mm deep. 3. The palladium membrane hydrogen separation device based on high temperature preheating according to claim 1, characterized in that: round holes are opened around the blind flange for bolt fixing during assembly. 4. The palladium membrane hydrogen separation device based on high temperature preheating according to claim 1, characterized in that: the side of the blind flange and the palladium membrane module connected to the synthesis gas circulation frame is respectively provided with grooves in the shape of a rectangle Groove, the width of the groove is 3-7 mm, and the depth is 1-3 mm. 5. The palladium membrane hydrogen separation device based on high temperature preheating according to claim 1, characterized in that: the width of the boss of the synthesis gas circulation frame is 0.3 narrower than the width of the blind flange and the groove of the palladium membrane module -0.7mm, the height is the same as the groove depth of the blind flange and palladium membrane assembly. 6. The palladium membrane hydrogen separation device based on high temperature preheating according to claim 1, characterized in that: the graphite gasket is a rectangular gasket made of high temperature resistant graphite, the width of which is the same as that of the blind flange and the palladium membrane assembly The grooves are the same width and 0.3-0.5 mm thick.

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