CN201283263Y - Membrane separation equipment for preparing high-purity hydrogen - Google Patents

Abstract

The utility model discloses a membrane separation device for preparing high-purity hydrogen, which comprises a palladium membrane assembly, a synthetic gas circulation frame, a blind flange, a graphite gasket, connecting bolts and nuts; A plurality of palladium membrane modules, between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module are provided with a syngas circulation frame, between the blind flange and the syngas circulation frame and between the syngas circulation frame and the palladium membrane module Graphite gaskets are installed between the palladium membrane modules; 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 a hydrogen-containing synthesis gas is installed in the synthesis gas circulation frame. The import and export pipes communicate with the gas circulation space of the palladium membrane module; bosses are arranged around the synthesis gas circulation frame. The utility model directly introduces the hydrogen-containing synthesis gas into both sides of the palladium membrane module, has compact design, small volume, convenient disassembly, can be purified and separated to obtain high-purity hydrogen, and has a high hydrogen permeability.

Description

Membrane separation equipment for the production of high-purity hydrogen

Technical field:

The utility model relates to a membrane separation device for separating hydrogen-containing synthesis gas for preparing high-purity hydrogen, in particular to a membrane separator with compact structure and easy expansion. The device can produce high-purity hydrogen from hydrogen-containing mixed gas.

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 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 Sievert's Law:

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

In the formula:

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

There are two main methods of using palladium membrane separation to produce hydrogen: A) The membrane module is coupled with the hydrogen production reactor to form a membrane reactor, and the reactor is used to react and separate the raw material gas to obtain high-purity hydrogen in one step. . The coupling of membrane separation and reaction process can break the thermodynamic balance of the reaction, making the reaction favor the direction of hydrogen production. However, due to the addition of membrane separation components in the reactor, the structure of the reactor is complex, the palladium membrane is in direct contact with the reaction medium and the catalyst, the operating conditions are relatively harsh, and the life of the palladium membrane is short. B) Palladium membrane separation is separated from the hydrogen production reactor. The hydrogen production reactor produces hydrogen-containing synthesis gas, and its downstream adopts palladium membrane separation to obtain high-purity hydrogen. This method is simple in process and convenient in operation and maintenance.

The Chinese invention patent application "A Quick 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 metal 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 small-scale channel is a heating channel passing through the membrane support frame. 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 component to the required working temperature, reduces the metal content of the palladium alloy membrane component, and further reduces the heating time.

In the usual application of the palladium membrane separation module, the palladium membrane separation module is generally placed in a pressure vessel, and the hydrogen gas outlet pipe is led out of the pressure vessel through the pressure vessel flange. The hydrogen-containing synthesis gas is introduced into the pressure vessel, and the hydrogen in it passes through the palladium membrane, and then is drawn out of the pressure vessel through the hydrogen outlet pipe. Since the pressure vessel is generally a circular structure with a built-in rectangular palladium membrane separation module, this type of application generally has a relatively large structure and is difficult to expand. The utility model sets a rectangular synthesis gas circulation frame on both sides of the palladium membrane separation component, directly introduces the hydrogen-containing synthesis gas to both sides of the palladium membrane separation component, and the formed palladium membrane separator has a compact structure and is easy to expand.

Utility model content

The utility model provides a palladium membrane separation device with a compact structure and easy expansion, aiming at the hydrogen-containing synthesis gas produced in chemical production and laboratories, with a palladium membrane module as the main component.

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

Membrane separation equipment for preparing high-purity hydrogen, including palladium membrane modules, is characterized in that the device also includes a synthesis gas circulation frame, blind flanges, graphite gaskets, connecting bolts and nuts; between the two blind flanges There are multiple palladium membrane modules between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module. A graphite gasket is installed between the circulation frame and the palladium membrane assembly;

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;

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. There is a cavity in the middle; the square frame forms a closed space with the blind flange or the palladium membrane module. The hydrogen-containing synthesis gas inlet and outlet pipes are arranged on the synthesis gas circulation frame, and bosses and bosses are processed around the synthesis gas circulation frame. The width 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 grooves provided around the side where the blind flange and the palladium membrane module are 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.

Compared with other hydrogen separation technologies such as pressure swing adsorption, the utility model has the following advantages:

(1) The quantity of palladium membrane module and syngas flow frame in the utility model device can be determined according to the required hydrogen output and operating conditions, and the basic structural type of the separator is not changed by the amount of the quantity, only increasing or decreasing the palladium membrane module and The number of syngas circulation frames is enough, and the load range can not only meet the demand of hydrogen production of hundreds of cubic meters per hour in chemical production, but also can be used for the production of several liters of hydrogen per hour in the laboratory.

(2) The device of the utility model adopts the design of a rectangular synthesis gas circulation frame, and directly introduces the hydrogen-containing synthesis gas into both sides of the palladium membrane module, which is compact in design, small in size and easy to disassemble.

(3) Using a palladium alloy membrane with a thickness as low as 10 microns, high-purity hydrogen can be purified and separated, and the hydrogen permeability is high.

Description of drawings

Figure 1. Assembly diagram of membrane separation equipment used to produce 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. Schematic diagram of the syngas circulation frame structure.

Figure 6-2 The C-C sectional view of Figure 6-1.

Figure 7-1. Schematic diagram of blind flange structure.

Figure 7-2 D-D section view of 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 separation device for producing high-purity hydrogen includes five components: palladium membrane module 1, synthesis gas circulation frame 2, blind flange 3, graphite gasket 4, bolts and nuts 5 . A plurality of palladium membrane modules are arranged between the two blind flanges 3, and a synthesis gas circulation frame 2 is arranged between the blind flange and the palladium membrane module and between the palladium membrane module and the palladium membrane module, and the synthesis gas circulation frame 2 Separation. In order to keep the seal, 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. Syngas circulation frame, graphite gasket, blind flange, all fixed by connecting bolts and nuts.

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 groove 103 with a width of 3-7 mm, preferably 5 mm, and a depth of 1-3 mm, preferably 1 mm; The graphite gasket 4 is docked with the boss 203 of the syngas circulation frame 2 (Figure 2.).

As shown in Figures 6-1 and 6-2, the synthesis gas circulation frame 2 is a stainless steel square frame with a cavity in the middle. 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 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 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 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 introduce high-temperature inert gas into the synthesis gas circulation frame through the synthesis gas inlet and outlet 202 to heat the membrane separation device. The hydrogen mixed gas is introduced by the introduction pipe 202 of the syngas circulation frame 2. In the hydrogen-containing gas circulation channel, the hydrogen in the mixed gas contacts the palladium membrane 106, and is transferred to the hydrogen gas circulation channel 102 through the palladium membrane 106 and the sintered metal 105, and then The palladium membrane separation device is drawn out from the hydrogen gas lead-out pipe 104 to become high-purity product hydrogen.

In the usual application of the palladium membrane separation module, the palladium membrane separation module is generally placed in a pressure vessel, and the hydrogen gas outlet pipe is led out of the pressure vessel through the pressure vessel flange. The hydrogen-containing synthesis gas is introduced into the pressure vessel, and the hydrogen in it passes through the palladium membrane, and then is drawn out of the pressure vessel through the hydrogen outlet pipe. Since the pressure vessel is generally a circular structure with a built-in rectangular palladium membrane separation module, this type of application has a relatively large structure and is difficult to expand. The utility model sets a rectangular synthesis gas circulation frame on both sides of the palladium membrane separation component, directly introduces the hydrogen-containing synthesis gas to both sides of the palladium membrane separation component, and the formed palladium membrane separator has a compact structure and is easy to expand.

Claims (6)

1, be used to prepare the membrane separation plant of high-purity hydrogen, comprise palladium membrane component, it is characterized in that, this device also comprises synthesis gas circulation framework, blank flange, Graphite pad, connecting bolt and nut; Between two blank flanges, be provided with a plurality of palladium membrane components, be provided with synthesis gas circulation framework between blank flange and the palladium membrane component and between palladium membrane component and the palladium membrane component, reach between synthesis gas circulation framework and the palladium membrane component between blank flange and the synthesis gas circulation framework Graphite pad is installed;

Described synthesis gas circulation framework is a quadra, and the centre is a cavity; Quadra and blank flange or palladium membrane component form the space of sealing, are provided with hydrogen containing synthesis gas at synthesis gas circulation framework and import and delivery line, and importing and delivery line are communicated with the gas communication space of palladium membrane component; Around synthesis gas circulation framework, be provided with boss;

Described blank flange is a square plate; All around be respectively equipped with groove with palladium membrane component with the one side that synthesis gas circulation framework is connected at blank flange, be provided with graphite gasket in the groove, the boss of synthesis gas circulation framework and the groove on blank flange and the palladium membrane component are tightly connected, on around the blank flange, open circular hole, bolting when being used to assemble.

2, the membrane separation plant that is used to prepare high-purity hydrogen according to claim 1, it is characterized in that: the film support frame both sides of described palladium membrane component have porous sintered metal supporter and palladium alloy membrane respectively, the film support frame contains and is cleaned the hydrogen gas stream circulation passage, this passage is the rectangular toothed combination of two symmetries, channel width is the 3-5 millimeter, support frame between the passage is the 3-5 millimeter, and the gas export mouth is arranged on support frame two ends up and down, is communicated with gas channel; Process a rectangular recess that is used for synthesis gas circulation frame seal around the described film support frame, wide 3-7 millimeters, dark 1-3 millimeters of described groove.

3, the membrane separation plant that is used to prepare high-purity hydrogen according to claim 1 is characterized in that: described synthesis gas circulation framework is the square framework of stainless steel.The centre is a cavity; Quadra and blank flange or palladium membrane component form the space of sealing, being provided with hydrogen containing synthesis gas at synthesis gas circulation framework imports and delivery line, around synthesis gas circulation framework, be processed with boss, the boss width is narrower 0.3-0.7 millimeter than the width of the groove of blank flange and palladium membrane component, and height is identical with the depth of groove of blank flange and palladium membrane component.

4, the membrane separation plant that is used to prepare high-purity hydrogen according to claim 1, it is characterized in that: the groove that the one side that described blank flange and palladium membrane component and synthesis gas circulation framework are connected is respectively equipped with all around is a rectangular recess, and described recess width is that 3-7 millimeters, the degree of depth are 1-3 millimeters.

5, the membrane separation plant that is used to prepare high-purity hydrogen according to claim 1, it is characterized in that: the boss width of described synthesis gas circulation framework is narrower 0.3-0.7 millimeter than the width of the groove of blank flange and palladium membrane component, and height is identical with the depth of groove of blank flange and palladium membrane component.

6, membrane separation plant according to claim 1 is characterized in that: the rectangle packing ring of described graphite gasket for being made by resistant to elevated temperatures graphite, width is identical with the width of the groove of blank flange and palladium membrane component, thick 0.3-0.5 millimeter.

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