CN201300029Y - Membrane separator for producing high-purity hydrogen via electric heating - Google Patents

Abstract

The utility model discloses a membrane separator for producing high-purity hydrogen by electric heating. The membrane separator is provided with a plurality of palladium membrane components between two blind flanges, and palladium membrane components between the blind flange and the palladium membrane components There is a synthesizer circulation frame between the membrane module and the palladium membrane module, graphite gaskets are installed between the blind flange and the synthesis gas circulation frame and between the synthesis gas circulation frame and the blind flange; the synthesis gas circulation frame is a square frame , with a cavity in the middle; a closed space is formed between the square frame and the blind flange or palladium membrane module, and hydrogen-containing synthesis gas import and export pipes are arranged on the synthesis gas circulation frame; bosses are arranged around the synthesis gas circulation frame, four The wall is provided with grooves, electric heating wires are arranged in the grooves, and insulating and heat-preserving materials are arranged outside the electric heating wires. The utility model directly introduces hydrogen-containing synthesis gas to both sides of the palladium membrane module, has small volume, convenient disassembly, fast heating rate, good temperature control effect, continuous production of high-purity hydrogen, and high hydrogen transmission rate.

Description

A membrane separator for producing high-purity hydrogen by electric heating

technical field

The utility model relates to a membrane separator with compact structure and easy expansion, which is used for separating and producing high-purity hydrogen from hydrogen-containing synthesis, especially relates to a membrane separator which adopts electric preheating, constant temperature, easy heating and good temperature control effect membrane separator. The membrane separator can produce high-purity hydrogen from hydrogen-containing gas mixture.

Background technique

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 the requirements of fuel cells; in addition, palladium membrane separators occupy a small area and are 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 Sievert's 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 application of palladium membrane separation to produce hydrogen 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. For example, some micro-scale channels can be processed on the palladium membrane components. Using electric heating or thermal fluid heating, this method has a relatively fast 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.

The Chinese invention patent "A Rapid Start Palladium Membrane Module Utilizing Microscale Channel Heat Transfer" (application number: 200710031743.5) discloses a palladium membrane module, which includes a membrane support frame, a porous metal support and a palladium alloy membrane , the two porous supports and the palladium alloy membrane are respectively located on both sides of the membrane support frame. The membrane support frame contains a purified hydrogen gas flow channel and a small-scale channel. The gas circulation channel has a rectangular cross-section, with a cross-sectional size of 0.2-1.0 mm × 0.2-1.0 mm, and the inlet and outlet of the small-scale channel are connected on the support frame containing the membrane; the hydrogen gas flow channel on the support body is rectangular tooth-shaped, The gas outlet is arranged at the upper end of the support frame. The component utilizes the flow and heat transfer of the thermal fluid in the small-scale channel to quickly raise the temperature of the palladium alloy membrane module to the required working temperature (generally 450-600 degrees), further reducing the heating time and reducing the temperature of the palladium alloy membrane module. metal content.

The Chinese invention patent "A Palladium Membrane Module Containing a Ceramic Thermal Insulation Layer and Utilizing Small-scale Channels for Heat Exchange" (application number: 200810029464.X) discloses another palladium membrane module. The module is provided with porous metal support sheets and palladium membranes from inside to outside on both sides of the membrane support frame. The membrane support frame contains purified hydrogen flow channels and small-scale channels. The gas circulation channel for heating has a rectangular cross-section, and the channel inlet and outlet connecting the small-scale channels are set on the support frame containing the membrane; the hydrogen gas flow channel of the membrane support frame is located in the center of the membrane support frame. The outer sides of the palladium alloy film are respectively provided with ceramic heat insulation layers. The component utilizes the circulation and heat transfer of high-temperature or low-temperature fluid in the small-scale channel and the heat insulation effect of the ceramic layer, which can make the operating temperature of the membrane different from the working temperature of the medium outside the component, thereby ensuring that even if the membrane is at the optimum operating temperature (generally 450-600°C), and make the hydrogen production process outside the component run at its optimum temperature.

Chinese invention patents (200710031743.5, 200810029464.X) involve adding micro-scale heating channels on the palladium membrane module. This method has a fast heating rate and saves materials. Difficulties. Aiming at this situation, this patent designs a simple electric heating and constant temperature membrane separator.

Utility model content

The utility model is aimed at the hydrogen-containing synthesis gas produced in the chemical industry and the laboratory. The main component is the palladium membrane module, and the electric heating is the main heating method. It provides a compact structure, easy expansion, preheating/constant temperature, and effective Better electrically heated palladium membrane separator.

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

A membrane separator for electric heating to produce high-purity hydrogen, including palladium membrane components, auxiliary equipment such as synthesis gas circulation frame, blind flange, graphite gasket, connecting bolts and nuts, is characterized in that the synthesis gas in the membrane separator The four walls of the circulation frame contain electric heating wires. There are multiple palladium membrane modules between the two blind flanges, a synthetic gas circulation frame is arranged between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module, and the blind flange and the syngas Graphite gaskets are installed between the flow frames and between the synthesis gas flow frame and 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 a blind flange or a palladium membrane module, and a hydrogen-containing synthesis gas import and export pipe is arranged on the synthesis gas circulation frame, and the import and export The tube communicates with the gas circulation space of the palladium membrane module; bosses are provided around the synthesis gas circulation frame; grooves are provided on the four walls of the synthesis gas circulation frame, electric heating wires are provided in the grooves, and electric heating wires are provided on the outside of the synthesis gas circulation frame. Insulation insulation material.

The blind flange is a square plate; grooves are respectively provided around the side where the blind flange and the palladium membrane module are connected to the synthesis gas circulation frame, and graphite gaskets are arranged in the grooves, and the bosses of the synthesis gas circulation frame are in contact with the syngas circulation frame. The blind flange and the groove on the palladium membrane module are sealed and connected, and round holes are opened around the blind flange for bolt fixing during assembly.

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 assembly, and the membrane support frame contains a purified hydrogen gas flow passage, which is two symmetrical Rectangular tooth-shaped combination, the 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 A rectangular groove for sealing with the synthetic gas circulation frame, the groove is 3-7 mm wide and 1-3 mm deep.

The synthesis gas circulation frame is a stainless steel square frame with a cavity in the middle and grooves on the four walls; the square frame forms a closed space with a blind flange or a palladium membrane module, and a hydrogen-containing synthesis gas is introduced into the synthesis gas circulation frame. And the outlet pipe, a boss is processed around the syngas circulation frame, the width of the boss is 0.3-0.7 mm narrower than the width of the groove of the blind flange and the palladium membrane module, and the height is the same as the groove of the blind flange and the palladium membrane module The grooves have the same depth, and the four walls of the synthesis gas circulation frame are processed into rectangular grooves (except the inlet and outlet pipes). The groove width is 3-5 mm and the depth is 3-5 mm. Electric heating wires are placed in the grooves. The power of the electric heating wire is determined according to the amount of hydrogen produced, and an insulating material is placed outside the electric heating wire.

The grooves provided around the side of the blind flange and the palladium membrane assembly connected to the synthesis gas circulation frame are 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 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.

In the utility model, electric heating is adopted for the separator, which is easy to implement in the laboratory, has a fast heating rate, and is easy to control the temperature.

Description of drawings

Figure 1. Assembly diagram of a membrane separator for the production of high-purity hydrogen.

Figure 2. Partial enlarged view of Figure 1.

Figure 3. Half-section view of palladium membrane module.

Figure 4. Sectional view of palladium membrane module A-A in Figure 3.

Figure 5. Sectional view of palladium membrane module B-B in Figure 3.

Figure 6-1. Right side view of syngas circulation frame.

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

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

Figure 7-1. Syngas Flow Frame Assembly Right View.

Figure 7-2. Figure 7-1 Syngas circulation frame assembly D-D section view.

Figure 7-3. Figure 7-2 Syngas circulation frame assembly C-C section view.

Figure 8-1. Schematic diagram of blind flange structure.

Figure 8-2. Figure 8-1 E-E cross-sectional view of the blind flange structure.

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 membrane separator for producing high-purity hydrogen by electric heating includes a palladium membrane module 1, a synthesis gas circulation frame 2, a blind flange 3, a graphite gasket 4, bolts and nuts 5, an electric heating Silk 205. 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 entire device is N, the number of syngas circulation frames required is N+1, the number of graphite gaskets is 2N+3, and the number of blind flanges is 2. To heat the membrane separator, electric heating wires 205 are placed in the grooves on the four walls of the synthesis gas circulation frame, and the power of the electric heating wires is selected according to the size of the membrane separator. For example, when the number of syngas circulation frames is 2, the number of palladium membrane modules is 1, and the number of blind flanges is 2, the size of the syngas circulation frame is 82×186×6-60×164×6 mm, and the palladium membrane module The size of the blind flange is 82×186×6mm, the size of the blind flange is 122×226×6mm, the thickness of the insulation material is 50mm, and the external temperature of the insulation material is required to be 50 degrees, and the temperature rises from 25°C to 600 ℃, the heating rate is 3 degrees per minute, then the power of the electric heating wire required in the heating stage is 120W, and the power of the electric heating wire required in the constant temperature stage is 25W. If the number of syngas circulation frames is 4, the number of palladium membrane modules is 2, and the number of blind flanges is 2, the power of the electric heating wire required in the heating stage is 150W, and the power of the electric heating wire required in the constant temperature stage is 32W . Syngas circulation frame, graphite gasket, blind flange, all fixed by connecting bolts and nuts. Temperature control box for heating and constant temperature stage control. At present, the temperature control box can be controlled manually or automatically.

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, the support frame between the channels is 3-5 mm, and the gas outlet 104 is set at the upper and lower ends of the support frame 101 and communicates with the air flow channel 104 . 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. 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. Membrane support frame 101 is processed around the width of 3-7 mm, preferably 5 mm, deep 1-3 mm, the groove 103 of preferably 1 mm; when assembling, add a groove 103 with a thickness of 0.3-0.5 mm and a width of 5 mm in the groove 103. The graphite gasket 4 is docked with the boss 203 of the syngas circulation frame 2 (Figure 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, in which the synthesis gas can flow and have a certain residence time. 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 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 ). As shown in Figures 7-1, 7-2, and 7-3, the four walls of the synthesis gas circulation frame are processed into a rectangular groove 204 with a width of 3-5 mm and a depth of 3-5 mm. The heating wire 205 is used for preheating and constant temperature of the membrane separator, and the insulation material 206 is filled around the electric heating wire to reduce the heat loss of the membrane separator and the conduction of the membrane separator.

As shown in Figures 8-1 and 8-2, 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 syngas flow frame 2, the width is 5 mm, and the depth is a rectangular groove 302 of 1 mm; when assembling (Fig. 1), the thickness of the groove 302 is increased by 0.3-0.5 mm. The graphite gasket 4 with a width of 5 mm is then sealed with the boss 203 of the synthesis gas circulation frame 2 .

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

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 separator 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, the membrane separator is first preheated by the electric heating wire 205, and 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 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. The preheating of the membrane separator and the temperature control of the constant temperature stage are controlled by a temperature control box.

In the usual heating method of membrane separator, high-temperature inert gas is generally used or the inside of the palladium membrane is processed into a scale channel. It is difficult to use high-temperature inert gas to heat the membrane separator in the laboratory, and the temperature is not easy to control. Since the high-temperature inert gas is introduced through the introduction pipe of the synthesis gas circulation frame, the heat cannot be supplemented immediately during the process of hydrogen separation and purification. The utility model adopts a rectangular groove with a certain width and a certain depth processed on the four walls of the synthesis gas circulation frame, and an electric heating wire is placed in the groove, and the membrane separator is preheated and kept at a constant temperature by electric heating, which is easy to realize in the laboratory. The heating rate is fast, and the temperature is easy to control.

Claims (6)

1. A membrane separator for electric heating to produce high-purity hydrogen, characterized in that: a plurality of palladium membrane components are arranged between two blind flanges, between the blind flange and the palladium membrane components and between the palladium membrane components and the palladium membrane components A syngas circulation frame is provided between the palladium membrane modules, 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 synthesis gas circulation frame is a square frame with a cavity in the middle; the square frame forms a closed space with a blind flange or a palladium membrane module, and a hydrogen-containing synthesis gas import and export pipe is arranged on the synthesis gas circulation frame, and the import and export The tube communicates with the cavity in the synthesis gas circulation frame of the palladium membrane module; there are bosses around the synthesis gas circulation frame, grooves on the four walls, electric heating wires in the grooves, and electric heating wires on the outside. insulation materials; The blind flange is a square plate; grooves are respectively provided around the side where the blind flange and the palladium membrane module are connected to the synthesis gas circulation frame, and graphite gaskets are arranged in the grooves, and the bosses of the synthesis gas circulation frame are in contact with the syngas circulation frame. The blind flange and the groove on the palladium membrane module are sealed and connected, and round holes are opened around the blind flange for bolt fixing during assembly. 2. The membrane separator for producing high-purity hydrogen by electric heating 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 membrane separator for producing high-purity hydrogen by electric heating according to claim 1, characterized in that: the rectangular grooves arranged on the four walls of the synthesis gas circulation frame have a width of 3-5 mm and a depth of 3-5 mm. 4. The electric heating membrane separator for producing high-purity hydrogen according to claim 1, characterized in that: the blind flange and the palladium membrane module are connected to the syngas flow frame and the grooves are respectively provided around the side of the frame. A rectangular groove, the width of the groove is 3-7 mm, and the depth is 1-3 mm. 5. The membrane separator for producing high-purity hydrogen by electric heating 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 assembly -0.7mm, the height is the same as the groove depth of the blind flange and palladium membrane assembly. 6. The membrane separator for producing high-purity hydrogen by electric heating 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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