Equipment for separating hydrogen and nitrogen

Abstract

The utility model provides equipment for separating hydrogen and nitrogen, and relates to the technical field of polycrystalline silicon. The device comprises a waste gas filtering device, a cryogenic device, an adsorption device and a gas membrane separation device which are communicated in sequence, a pressure swing adsorption device is communicated with the gas membrane separation device, a nitrogen purification device is communicated with the gas membrane separation device, and permeation gas output by the gas membrane separation device enters the pressure swing adsorption device. The impermeable gas output by the gas film separation device enters the nitrogen purification device; the nitrogen purification device comprises a dehydrogenation device, an oxygen absorption tower, a water removal mechanism and a storage tank which are communicated in sequence, a dehydrogenation catalyst is arranged in the dehydrogenation device, and the dehydrogenation device is communicated with an oxygen pipe. According to the utility model, hydrogen and nitrogen in vent gas after waste gas treatment in a plant are separated, so that the hydrogen and nitrogen are recycled.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon, in particular to a device for separating hydrogen and nitrogen. Background Art

[0002] Polycrystalline silicon is a form of elemental silicon. When molten elemental silicon solidifies under supercooling conditions, silicon atoms are arranged into many crystal nuclei in the form of diamond lattices. If these crystal nuclei grow into grains with different crystal plane orientations, these grains will combine and crystallize into polycrystalline silicon.

[0003] In the prior art, the exhaust gas from the entire plant includes dust-containing exhaust gas and dust-free exhaust gas. The dust-containing exhaust gas contains solid silicon powder. The exhaust gas from the entire plant is discharged after treatment. The components of the discharged air are hydrogen and nitrogen. The emission of hydrogen and nitrogen not only causes waste, but also there is a risk of hydrogen emission, which may cause explosion or fire. Utility Model Content

[0004] The utility model aims to develop a device for separating hydrogen and nitrogen which can separate hydrogen and nitrogen from the vented air after the waste gas treatment in the factory and realize the recycling of hydrogen and nitrogen.

[0005] The utility model is achieved through the following technical solutions:

[0006] A device for separating hydrogen and nitrogen, comprising:

[0007] An exhaust gas filtering device, a cryogenic device, an adsorption device, and an air membrane separation device connected in sequence;

[0008] A pressure swing adsorption device is connected to the gas membrane separation device;

[0009] A nitrogen purification device connected to the gas membrane separation device;

[0010] The permeate gas outputted by the gas membrane separation device enters into the pressure swing adsorption device, and the non-permeate gas outputted by the gas membrane separation device enters into the nitrogen purification device;

[0011] The nitrogen purification device comprises a dehydrogenator, an oxygen absorption tower, a water removal mechanism and a storage tank which are connected in sequence. A dehydrogenation catalyst is arranged in the dehydrogenator, and an oxygen pipe is connected to the dehydrogenator.

[0012] Optionally, the exhaust gas filtering device includes a silicon powder filter and an exhaust gas buffer tank which are connected to each other. The exhaust gas buffer tank is connected to a cryogenic device. A compressor is provided on the pipeline between the exhaust gas buffer tank and the cryogenic device. The silicon powder filter is connected to a dust-containing exhaust gas pipe, and the exhaust gas buffer tank is connected to a dust-free exhaust gas pipe.

[0013] Optionally, the exhaust gas filtering device further includes a venting mechanism, which includes a leaching tower, a water seal tank and a flame arrester which are sequentially connected to the exhaust gas buffer tank, and the flame arrester is connected to the outside.

[0014] Optionally, the gas membrane separation device includes a venting waste gas buffer tank, a venting waste gas compressor, a filtering mechanism, a heat exchanger and a separation membrane mechanism which are connected in sequence, and the venting waste gas buffer tank is connected to the adsorption device.

[0015] Optionally, the filtering mechanism includes two sets of parallel filtering components, and the filtering components include a first filter and a second filter that are connected.

[0016] Optionally, the filtration accuracies of the first filter and the second filter are 1µm and 0.01µm respectively.

[0017] Optionally, the separation membrane mechanism includes primary membrane separation, secondary membrane separation, a hydrogen buffer tank and a nitrogen buffer tank. The primary membrane separation is connected to a heat exchanger, a hydrogen buffer tank and a secondary membrane separation. The secondary membrane separation is connected to a nitrogen buffer tank and a venting waste gas buffer tank. The hydrogen buffer tank is connected to a pressure swing adsorption device, and the nitrogen buffer tank is connected to a nitrogen purification device.

[0018] Optionally, the primary membrane separation uses a high-selectivity membrane component, and the secondary membrane separation uses a high-flux membrane component.

[0019] Optionally, the water removal mechanism includes two groups of water removal components connected in parallel, and the water removal components include a cold dryer and an adsorption dryer connected in series.

[0020] The beneficial effects of the utility model are:

[0021] The utility model processes the dust-containing waste gas and the dust-free waste gas in the factory to obtain a nitrogen and hydrogen mixed gas, separates and purifies the mixed gas to realize the recycling of the nitrogen and hydrogen, which not only avoids the explosion and fire that may occur when the hydrogen in the mixed gas is emptied, improves the safety of the factory area, but also the purified nitrogen and hydrogen have high purity and can be used directly, thus reducing energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of a gas membrane separation device;

[0024] Figure 2 It is a structural schematic diagram of the nitrogen purification device.

[0025] Figure numerals: 1. Vent exhaust buffer tank; 2. Vent exhaust compressor; 3. Filter mechanism; 301. First filter; 302. Second filter; 4. Heat exchanger; 5. Primary membrane separation; 6. Hydrogen buffer tank; 7. Secondary membrane separation; 8. Nitrogen buffer tank; 9. Dehydrogenator; 10. Oxygen absorption tower; 11. Cold dryer; 12. Adsorption dryer; 13. Storage tank. DETAILED DESCRIPTION

[0026] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0027] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0028] The utility model discloses a device for separating hydrogen and nitrogen, comprising a waste gas filtering device, a cryogenic device, an adsorption device and a gas membrane separation device which are connected in sequence, and also comprises a pressure swing adsorption device and a nitrogen purification device which are connected to the gas membrane separation device.

[0029] The exhaust gas filtering device includes a silicon powder filter and an exhaust gas buffer tank which are connected to each other. The exhaust gas buffer tank is connected to a cryogenic device. A compressor is arranged on the pipeline between the exhaust gas buffer tank and the cryogenic device. The silicon powder filter is connected to a dust-containing exhaust gas pipe, and the exhaust gas buffer tank is connected to a dust-free exhaust gas pipe. After the dust-containing exhaust gas enters the silicon powder filter to filter the silicon powder, it is sent to the exhaust gas buffer tank to be mixed with the dust-free exhaust gas and then pressurized and input into the cryogenic device.

[0030] The exhaust gas is cryogenically cooled by circulating water and -70°C dichloromethane in the cryogenic device to remove chlorosilane in the exhaust gas. The exhaust gas then passes into the adsorption device, and the activated carbon adsorption column in the adsorption device adsorbs the hydrogen chloride and trace silane that have not been cryogenically cooled.

[0031] The exhaust gas filtering device also includes a venting mechanism. When the cryogenic device or the adsorption device is abnormal, the exhaust gas in the exhaust gas buffer tank is vented by the venting mechanism. The venting mechanism includes a leaching tower, a water seal tank and a flame arrester which are sequentially connected to the exhaust gas buffer tank, and the flame arrester is connected to the outside.

[0032] like Figure 1As shown, the gas membrane separation device includes a venting waste gas buffer tank 1, a venting waste gas compressor 2, a filtering mechanism 3, a heat exchanger 4 and a separation membrane mechanism which are connected in sequence. The venting waste gas buffer tank 1 is connected to the adsorption device. The filtering mechanism 3 includes two sets of parallel filtering components. The filtering components include a first filter 301 and a second filter 302 which are connected. The filtering accuracies of the first filter 301 and the second filter 302 are 1µm and 0.01µm respectively. The two sets of filtering components are used in one and reserved in the other to ensure that the system does not stop running when the filter element is replaced.

[0033] The separation membrane mechanism includes a primary membrane separation 5 and a secondary membrane separation 7. The primary membrane separation 5 is connected to the heat exchanger 4, the hydrogen buffer tank 6 and the secondary membrane separation 7. The secondary membrane separation 7 is connected to the nitrogen buffer tank 8 and the exhaust gas buffer tank 1. The hydrogen buffer tank 6 is connected to the pressure swing adsorption device, and the nitrogen buffer tank 8 is connected to the nitrogen purification device. The primary membrane separation 5 adopts a high-selectivity membrane component, and the secondary membrane separation 7 adopts a high-flux membrane component.

[0034] The waste gas in the venting waste gas buffer tank 1 is input into the primary membrane separation 5 after pressurization, filtration and heat exchange, the permeate gas of the primary membrane separation 5 is input into the hydrogen buffer tank 6, and the retentate gas of the primary membrane separation 5 is input into the secondary membrane separation 7. The permeate gas of the secondary membrane separation 7 is sent back to the venting waste gas buffer tank 1, and the non-permeate gas of the secondary membrane separation 7 is input into the nitrogen buffer tank 8.

[0035] A compressor is provided between the hydrogen buffer tank 6 and the pressure swing adsorption device. The compressor pressurizes the hydrogen in the hydrogen buffer tank 6 to 0.9 MPa and then sends it to the pressure swing adsorption device to further purify the hydrogen so that the hydrogen reaches a usable purity.

[0036] like Figure 2 As shown, the nitrogen purification device includes a dehydrogenator 9, an oxygen absorption tower 10, a water removal mechanism and a storage tank 13 which are connected in sequence. The dehydrogenator 9 is connected to the nitrogen buffer tank 8. A dehydrogenation catalyst is arranged in the dehydrogenator 9. The dehydrogenator 9 is connected to an oxygen pipe.

[0037] The oxygen absorption tower 10 is provided with a high-efficiency deoxygenation adsorbent, which absorbs the residual oxygen in the gas. The dehydration mechanism includes two sets of dehydration components connected in parallel, one for use and one for standby, so that when one set of dehydration components is maintained, the other set of dehydration components can be used normally without stopping the equipment. The dehydration components include a cold dryer 11 and an adsorption dryer 12 connected in sequence to remove water from the nitrogen.

[0038] The utility model processes the dust-containing waste gas and the dust-free waste gas in the factory to obtain a nitrogen and hydrogen mixed gas, separates and purifies the mixed gas to realize the recycling of the nitrogen and hydrogen, which not only avoids the explosion and fire that may occur when the hydrogen in the mixed gas is emptied, improves the safety of the factory area, but also the purified nitrogen and hydrogen have high purity and can be used directly, thus reducing energy waste.

[0039] The above embodiments are only preferred embodiments of the present utility model and are not limitations on the technical solutions of the present utility model. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present utility model.

Claims

1. A device for separating hydrogen and nitrogen, characterized in that: include: An exhaust gas filtering device, a cryogenic device, an adsorption device, and an air membrane separation device connected in sequence; A pressure swing adsorption device is connected to the gas membrane separation device; A nitrogen purification device connected to the gas membrane separation device; The permeate gas outputted by the gas membrane separation device enters into the pressure swing adsorption device, and the non-permeate gas outputted by the gas membrane separation device enters into the nitrogen purification device; The nitrogen purification device comprises a dehydrogenator, an oxygen absorption tower, a water removal mechanism and a storage tank which are connected in sequence. A dehydrogenation catalyst is arranged in the dehydrogenator, and an oxygen pipe is connected to the dehydrogenator.

2. The device for separating hydrogen and nitrogen according to claim 1, characterized in that: The exhaust gas filtering device includes a silicon powder filter and an exhaust gas buffer tank which are connected to each other. The exhaust gas buffer tank is connected to a cryogenic device. A compressor is provided on the pipeline between the exhaust gas buffer tank and the cryogenic device. The silicon powder filter is connected to a dust-containing exhaust gas pipe, and the exhaust gas buffer tank is connected to a dust-free exhaust gas pipe.

3. The device for separating hydrogen and nitrogen according to claim 2, characterized in that: The exhaust gas filtering device also includes a venting mechanism, which includes a leaching tower, a water seal tank and a flame arrester that are sequentially connected to the exhaust gas buffer tank, and the flame arrester is connected to the outside.

4. The device for separating hydrogen and nitrogen according to claim 1, characterized in that: The gas membrane separation device comprises a venting waste gas buffer tank, a venting waste gas compressor, a filtering mechanism, a heat exchanger and a separation membrane mechanism which are connected in sequence, and the venting waste gas buffer tank is connected to the adsorption device.

5. The device for separating hydrogen and nitrogen according to claim 4, characterized in that: The filtering mechanism comprises two sets of parallel filtering components, and the filtering components comprise a first filter and a second filter which are connected in sequence.

6. The device for separating hydrogen and nitrogen according to claim 5, characterized in that: The filtration precisions of the first filter and the second filter are 1µm and 0.01µm respectively.

7. The device for separating hydrogen and nitrogen according to claim 4, characterized in that: The separation membrane mechanism includes primary membrane separation, secondary membrane separation, a hydrogen buffer tank and a nitrogen buffer tank. The primary membrane separation is connected with a heat exchanger, a hydrogen buffer tank and a secondary membrane separation. The secondary membrane separation is connected with a nitrogen buffer tank and a venting waste gas buffer tank. The hydrogen buffer tank is connected with a pressure swing adsorption device, and the nitrogen buffer tank is connected with a nitrogen purification device.

8. The device for separating hydrogen and nitrogen according to claim 7, characterized in that: The primary membrane separation adopts a high-selectivity membrane component, and the secondary membrane separation adopts a high-flux membrane component.

9. The device for separating hydrogen and nitrogen according to any one of claims 1 to 8, characterized in that: The dewatering mechanism comprises two sets of dewatering components connected in parallel, and the dewatering components comprise a cold dryer and an adsorption dryer connected in sequence.

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