Device and method for separating nitrogen from nitrogen-containing steam

Abstract

The present invention discloses a device and method for separating nitrogen from nitrogen-containing steam. The device includes a condensing device, a flash tank, and an ejector. The condensing device is connected to the flash tank through a water inlet pipe, and the ejector is connected to the inside of the flash tank. The middle of the flash tank is connected to a first nitrogen exhaust pipe, and the top of the flash tank is connected to a mixed exhaust pipe. The pipe body of the mixed exhaust pipe is connected to an upwardly extending riser, and the riser is connected to a second nitrogen exhaust pipe. The method includes the following steps in sequence: condensation, flash evaporation, discharge of middle-layer nitrogen, ejection to allow nitrogen steam mixed gas to enter a pipeline, and discharge nitrogen with reduced density upward from the pipeline. The device and method for separating nitrogen from nitrogen-containing steam provided by the present invention discharge the mixed gas after flash evaporation into the mixed exhaust pipe by ejection, the pressure in the mixed exhaust pipe increases, and the density of nitrogen and steam changes, thereby completely removing nitrogen from the steam and realizing steam recovery and reuse.

Description

Technical Field

[0001] The invention relates to the field of gas separation, and in particular to a device and a method for separating nitrogen from nitrogen-containing steam. Background Art

[0002] Tire vulcanization refers to the vulcanization of tires by pressurizing the model. During the vulcanization process, the outer tread of the tire is heated and formed, while the inner bladder needs to be cooled. At present, nitrogen filling is generally used to pressurize and condense the inner bladder. Therefore, after the tire is vulcanized, steam condensate containing nitrogen is generated, and direct discharge of this condensate will cause waste and affect economic benefits. If the steam condensate containing nitrogen is directly recycled in the field of heat exchange, due to the presence of non-condensable gas nitrogen, it will form a layer of air film on the surface, making heat exchange difficult.

[0003] According to research, when steam contains non-condensable gas, as the steam condenses, the non-condensable gas will gather at the interface, and the partial pressure of the non-condensable gas at the interface will be higher than the partial pressure of the non-condensable gas in the mainstream area. Therefore, while the steam diffuses to the gas-liquid interface, the non-condensable gas diffuses from the gas-liquid interface to the mainstream, forming a dynamic equilibrium process. Due to the non-condensable gas layer formed at the gas-liquid interface, the process of mainstream steam diffusing to the wall must pass through the gas boundary layer, which increases the condensation mass transfer resistance of the steam. At the same time, due to the presence of non-condensable gas, the partial pressure of steam near the gas-liquid interface is reduced, the saturation temperature of steam is reduced, and the heat transfer temperature difference between the steam and the condensation wall is reduced, which weakens the condensation process of the steam.

[0004] Therefore, the condensation heat exchange of steam containing non-condensable gases is more complicated than the condensation heat exchange of pure steam. Therefore, the steam condensate containing nitrogen generated after tire vulcanization needs to separate the nitrogen and recover the steam for subsequent condensation or other heat exchange processes. However, current technology cannot effectively separate nitrogen from steam. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a device and method for separating nitrogen from nitrogen-containing steam, which solves the problem of how to separate nitrogen and realizes the recovery of steam at the same time.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: an equipment for separating nitrogen from nitrogen-containing steam, comprising a condensing device, a flash tank, and an ejector, wherein the condensing device is provided with a feed pipe, the condensing device is connected to the flash tank through a water inlet pipe, the ejector is connected to the interior of the flash tank, a first nitrogen exhaust pipe is connected to the middle of the flash tank, a mixed exhaust pipe is connected to the top of the flash tank, a riser extending upward is connected to the pipe body of the mixed exhaust pipe, the riser is connected to a second nitrogen exhaust pipe, and the second nitrogen exhaust pipe discharges nitrogen in the mixed exhaust pipe.

[0007] Preferably, the condensing device is a condensing water tank, the feed pipes are multiple and all connected to the top of the condensing device, the bottom of the condensing device is connected to the upper side of the flash tank through an inlet pipe, and a valve is installed on the inlet pipe.

[0008] Preferably, the pressure in the condensing device is greater than the pressure in the flash tank.

[0009] Preferably, a liquid level display is provided on the flash tank.

[0010] Preferably, the end of the first nitrogen exhaust pipe away from the flash tank is closed, the end of the second nitrogen exhaust pipe away from the riser is closed, and the first nitrogen exhaust pipe and the second nitrogen exhaust pipe are connected to each other with a riser branch extending upward.

[0011] Preferably, a pressure-balanced exhaust valve is connected to the rising branch pipe.

[0012] Preferably, the bottom of the flash tank is connected to a drain pipe, and a valve is installed on the drain pipe.

[0013] The present invention also provides a method for separating nitrogen from nitrogen-containing steam, comprising the following steps:

[0014] S1: condensing steam mixed with nitrogen to form saturated condensed liquid;

[0015] S2: The saturated condensed liquid forms a nitrogen steam mixed gas at the top layer, nitrogen at the middle layer and a saturated liquid at the bottom layer after flash evaporation;

[0016] S3: Expelling the nitrogen in the middle layer, and causing the nitrogen-steam mixed gas to be discharged into the pipeline by ejection. Due to the increase in pressure in the pipeline caused by ejection, the density of the nitrogen is reduced to be less than the density of the steam;

[0017] S4: Discharge the nitrogen gas with reduced density upward from the pipeline.

[0018] Preferably, the flash evaporation pressure in S2 is 0.06-0.12 MPa.

[0019] Preferably, the pressure of the mixed gas in S3 is 0.4 MPa.

[0020] Preferably, the steam from which nitrogen is separated in S3 is recovered for heat exchange.

[0021] Beneficial effects of the present invention: The device and method for separating nitrogen from nitrogen-containing steam provided by the present invention discharge the mixed gas after flash evaporation into a mixed exhaust pipe by injection. The pressure in the mixed exhaust pipe increases, and the density of nitrogen and steam changes, thereby completely removing the nitrogen from the steam and realizing the recovery and reuse of the steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Among them: 1. Feed pipe, 2. Condensation equipment, 3. Water inlet pipe, 4. Flash tank, 5. Ejector, 6. Liquid level display, 7. First nitrogen exhaust pipe, 8. Mixing exhaust pipe, 9. Rising pipe, 10. Second nitrogen exhaust pipe, 11. Rising branch pipe, 12. Pressure balanced exhaust valve, 13. Drain pipe. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific implementation modes.

[0025] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "middle", "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The nitrogen-containing steam in the present invention refers to steam containing nitrogen.

[0028] like Figure 1 As shown, this embodiment provides a device for separating nitrogen from nitrogen-containing steam, including a condensing device 2, a flash tank 4, and an ejector 5.

[0029] The condensing device 2 is provided with a feeding pipe 1. The steam containing nitrogen and / or steam condensed water mixed with nitrogen generated after the tire is vulcanized is introduced into the feeding pipe 1. In order to improve the feeding efficiency, there are multiple feeding pipes 1 and all are connected to the top of the condensing device 2. The condensing device 2 is a condensing water tank, and the steam containing nitrogen and / or steam condensed water mixed with nitrogen generated after the tire is vulcanized are all converted into saturated liquid in the condensing device 2.

[0030] The condensing device 2 is connected to the flash tank 4 through the water inlet pipe 3. Specifically, the bottom of the condensing device 2 is connected to the upper side of the flash tank 4 through the water inlet pipe 3, and a valve is installed on the water inlet pipe 3. The pressure in the condensing device 2 is greater than the pressure in the flash tank 4, so the saturated liquid entering the flash tank 4 is flashed and becomes a mixed gas of liquid (water in this embodiment) and nitrogen vapor. Because the pressure in the flash tank 4 is relatively low, generally 0.06-0.12MPa, the nitrogen density at this time is greater than the density of steam. Therefore, the gas is divided into two layers, namely, the nitrogen distributed in the middle of the flash tank 4 and the steam and nitrogen mixed gas distributed in the upper part of the flash tank 4. It should be noted that the nitrogen in the middle of the flash tank 4 is not pure nitrogen, and a small amount of steam is mixed therein. Because the content of steam is less, the overall recovery efficiency of the steam is very small when discharged, so the nitrogen in the middle can be discharged directly. Due to the nature of the gas itself, steam and nitrogen will not be completely stratified, so the top layer forms a mixed gas of steam and nitrogen.

[0031] The ejector 5 is connected to the interior of the flash tank 4. The ejector 5 is used to inject an ejection flow into the flash tank 4 to eject the gas at the top of the flash tank 4 out of the flash tank 4. The ejector 5 is a prior art, so its structure is not described in detail. The middle of the flash tank 4 is connected to a first nitrogen exhaust pipe 7 for discharging nitrogen in the middle of the flash tank 4. The top of the flash tank 4 is connected to a mixed exhaust pipe 8 for discharging a steam-nitrogen mixed gas in the upper part of the flash tank 4.

[0032] The pipe body of the mixed exhaust pipe 8 is connected to an upwardly extending riser 9, and the riser 9 is connected to a second nitrogen exhaust pipe 10. Due to the effect of induced jets and the fact that the internal space of the mixed exhaust pipe 8 is much smaller than the internal volume of the flash tank 4, the pressure in the mixed exhaust pipe 8 increases. Since the density of nitrogen and steam changes with the pressure, the density change trends of the two are opposite. Therefore, when the pressure in the mixed exhaust pipe 8 reaches a certain level, the pressure of nitrogen will be lower than the pressure of steam. When the density of nitrogen is lower than the density of steam, nitrogen enters the second nitrogen exhaust pipe 10 from the riser 9, and then the second nitrogen exhaust pipe 10 discharges the nitrogen in the mixed exhaust pipe. The end of the mixed exhaust pipe 8 away from the flash tank 4 is set as a steam outlet, which discharges steam to facilitate the recycling of steam.

[0033] In order to prevent the first nitrogen exhaust pipe 8 from being lower than the liquid level in the flash tank 4, a liquid level display 6 is provided on the flash tank 4 to monitor the liquid level.

[0034] The bottom of the flash tank 4 is connected to a drain pipe 13, on which a valve is installed. The drain pipe 13 is used to discharge the liquid in the flash tank 4 for recycling and can also control the liquid level in the flash tank 4.

[0035] As a further preferred embodiment of the above technical solution, the end of the first nitrogen exhaust pipe 7 away from the flash tank 4 is closed, and the end of the second nitrogen exhaust pipe 10 away from the riser 9 is closed. The first nitrogen exhaust pipe 7 and the second nitrogen exhaust pipe 10 are connected to the pipe body with an upwardly extending riser branch 11. The riser branch 11 is connected to a pressure-balanced exhaust valve 12. When nitrogen is sealed in the first nitrogen exhaust pipe 7 and the second nitrogen exhaust pipe 10, the pressure of nitrogen gradually increases. When the pressure exceeds the threshold of the pressure-balanced exhaust valve 12, the nitrogen is discharged from the pressure-balanced exhaust valve 12. The pressure-balanced exhaust valve 12 is a prior art, and the steam system exhaust valve of Japan TLV Valve (China) Co., Ltd. can be selected, and its model is TLVLA13L.

[0036] This embodiment provides a method for separating nitrogen from nitrogen-containing steam, comprising the following steps:

[0037] S1: condensing steam mixed with nitrogen to form saturated condensed liquid;

[0038] S2: The saturated condensed liquid forms a nitrogen vapor mixed gas at the top layer, nitrogen at the middle layer and a saturated liquid at the bottom layer after flash evaporation;

[0039] S3: The nitrogen in the middle layer is discharged, and the nitrogen-steam mixed gas is discharged into the pipeline through the ejection. Since the pressure in the pipeline is increased by the ejection, the density of the nitrogen is reduced to less than the density of the steam;

[0040] S4: The nitrogen gas with reduced density is discharged upward from the pipeline.

[0041] The flash pressure in S2 is 0.06-0.12 MPa, and the mixed gas pressure in S3 is 0.4 MPa.

[0042] This embodiment also provides a method for separating nitrogen from nitrogen-containing steam based on the device for separating nitrogen from nitrogen-containing steam, which comprises the following steps:

[0043] S1: Nitrogen-containing steam and / or steam condensate mixed with nitrogen generated after tire vulcanization enters the condensation device 2 from the feed pipe 1 and condenses to form a saturated condensed liquid.

[0044] S2: The saturated condensed liquid enters the flash tank 4 and forms a nitrogen steam mixed gas at the top layer, nitrogen at the middle layer and a saturated liquid at the bottom layer through flash evaporation, wherein the pressure of the flash tank 4 is lower than the pressure of the condensing equipment 2.

[0045] S3: The nitrogen in the middle layer is discharged from the flash tank 4 through the first nitrogen exhaust pipe 7, and the nitrogen-steam mixed gas in the upper layer enters the mixed exhaust pipe 8 under the ejection effect of the ejector 5. The pressure in the mixed exhaust pipe 8 increases, and the density of nitrogen decreases to be less than the density of steam;

[0046] S4: The nitrogen enters the second nitrogen exhaust pipe 10 from the riser 9, and then the second nitrogen exhaust pipe 10 discharges the nitrogen in the mixed exhaust pipe.

[0047] In this embodiment, most of the nitrogen is first separated by flash evaporation, and the remaining nitrogen is separated by adjusting the specific gravity of nitrogen and steam by pressurization. In addition, the condensed water and steam after the nitrogen is separated can be recycled for heat exchange.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for separating nitrogen from nitrogen-containing steam, characterized in that: The invention comprises a condensing device (2), a flash tank (4), and an ejector (5), wherein the condensing device (2) is provided with a feed pipe (1), the condensing device (2) is connected to the flash tank (4) via a water inlet pipe (3), the ejector (5) is connected to the inside of the flash tank (4), the middle of the flash tank (4) is connected to a first nitrogen exhaust pipe (7), the top of the flash tank (4) is connected to a mixed exhaust pipe (8), the pipe body of the mixed exhaust pipe (8) is connected to an upwardly extending riser (9), the riser (9) is connected to a second nitrogen exhaust pipe (10), and the second nitrogen exhaust pipe (10) discharges nitrogen in the mixed exhaust pipe; the condensing device (2) is a condensing water tank, the feed pipe (1) is plural and all are connected to the top of the condensing device (2); The bottom of the condensing device (2) is connected to the upper side of the flash tank (4) through a water inlet pipe (3), and a valve is installed on the water inlet pipe (3); the pressure in the condensing device (2) is greater than the pressure in the flash tank (4); a liquid level display (6) is provided on the flash tank (4); the end of the first nitrogen exhaust pipe (7) away from the flash tank (4) is closed, and the end of the second nitrogen exhaust pipe (10) away from the riser (9) is closed; the first nitrogen exhaust pipe (7) and the second nitrogen exhaust pipe (10) are connected to the pipe body with a rising branch pipe (11) extending upward; the rising branch pipe (11) is connected to a pressure-balanced exhaust valve (12); the bottom of the flash tank (4) is connected to a drain pipe (13), and a valve is installed on the drain pipe.

2. A method for separating nitrogen from nitrogen-containing steam, characterized in that: The device for separating nitrogen from nitrogen-containing steam as claimed in claim 1 comprises the following steps: S1: condensing steam mixed with nitrogen to form saturated condensed liquid; S2: The saturated condensed liquid forms a nitrogen steam mixed gas at the top layer, nitrogen at the middle layer and a saturated liquid at the bottom layer after flash evaporation; S3: The nitrogen in the middle layer is discharged, and the nitrogen-steam mixed gas is discharged into the pipeline by injection. Since the pressure in the pipeline is increased by injection, the density of nitrogen is reduced to be less than the density of steam; the pressure of the mixed gas is 0.4 MPa; S4: Discharge the nitrogen gas with reduced density upward from the pipeline.

3. The method for separating nitrogen from nitrogen-containing steam according to claim 2, characterized in that: The flash evaporation pressure is 0.06-0.12MPa.

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