Low-temperature anti-swing type in-tower liquid pre-distributor

Abstract

The application designs a low-temperature anti-fluctuation type tower inner liquid pre-distributor, which comprises a distributor body, the distributor body is composed of a surrounding cylinder and a bottom plate, two semicircular air passages are arranged oppositely in the inside of the surrounding cylinder and penetrate through the bottom plate, a rectangular groove is arranged between the two semicircular air passages, the groove is provided with a liquid falling device, the liquid amount in the liquid pool is determined by adjusting the height of the middle liquid falling device, the liquid falling device and the air passage divide the surrounding cylinder into an annular liquid pool, and a liquid outlet is further arranged on one side wall of the surrounding cylinder. The novel pre-distributor can resist the interference of liquid level fluctuation on rectification in the tower and liquid interruption after liquid is pumped out in the tower.

Description

TECHNICAL FIELD

[0001] The application relates to a low-temperature anti-fluctuation type liquid pre-distributor in a tower, and belongs to the technical field of air separation devices. BACKGROUND

[0002] A double-tower process is widely applied in an air separation deep-cooling nitrogen production system due to a low energy consumption. In the double-tower process, part of liquid ammonia is extracted from a low-pressure nitrogen tower liquid distributor into a circulating pump for reflux according to a process requirement. A liquid storage pool is designed as a liquid nitrogen extraction buffer pool considering the influence of liquid extraction on a liquid level in the tower. The depth of the liquid storage pool is controlled by a guide pipe extending out of a bottom plate. Liquid flows from the guide pipe into the bottom liquid distributor again and is uniformly distributed into packing for rectification. However, the structure of the long pipe free outflow is simple, but for the sharp edge and the hole far away from the wall surface, the cross section is perfect contraction, and the liquid flow in the pipe is very unstable. In the actual operation process, the phenomenon of short-term liquid depletion flow breakage occurs.

[0003] Therefore, the low-temperature anti-fluctuation type liquid pre-distributor in the tower is designed to overcome the above problems. SUMMARY

[0004] The application aims to overcome the above problems and provide the low-temperature anti-fluctuation type liquid pre-distributor in the tower, which is used for overcoming the fluctuation of the liquid level in the tower after the liquid extraction from the liquid storage pool to provide the required liquid for the circulating pump, the severe fluctuation of the liquid flow from the long pipe free outflow into the bottom distributor or the packing, the short-term depletion flow breakage and the damage to the rectification condition of the fractionating tower. The new distributor designed in the application adopts the annular liquid storage pool, the middle liquid falling platform is used to determine the liquid amount in the liquid storage pool, so that the process requirement of the liquid nitrogen extraction is met. The two sides of the platform are the half-moon-shaped gas channels, so that the smoothness of the gas components is ensured, and the stable buffering effect of the liquid level after the liquid nitrogen extraction is met. The long pipe free outflow is changed into the nozzle free outflow, so that the vacuum caused by the perfect cross section contraction and the gasification of the liquid are avoided, and the fluctuation of the liquid flow is avoided. The liquid flow in the tower is more stable and efficient.

[0005] The application aims to overcome the above problems and provide the low-temperature anti-fluctuation type liquid pre-distributor in the tower, which is used for overcoming the fluctuation of the liquid level in the tower after the liquid extraction from the liquid storage pool to provide the required liquid for the circulating pump, the severe fluctuation of the liquid flow from the long pipe free outflow into the bottom distributor or the packing, the short-term depletion flow breakage and the damage to the rectification condition of the fractionating tower. The new distributor designed in the application adopts the annular liquid storage pool, the middle liquid falling platform is used to determine the liquid amount in the liquid storage pool, so that the process requirement of the liquid nitrogen extraction is met. The two sides of the platform are the half-moon-shaped gas channels, so that the smoothness of the gas components is ensured, and the stable buffering effect of the liquid level after the liquid nitrogen extraction is met. The long pipe free outflow is changed into the nozzle free outflow, so that the vacuum caused by the perfect cross section contraction and the gasification of the liquid are avoided, and the fluctuation of the liquid flow is avoided. The liquid flow in the tower is more stable and efficient.

[0006] As preferred: the liquid falling device is a liquid falling platform, which is a block-shaped water tank arranged between two semicircular air grooves, the two side edges of the water tank are parallel to the two side edges of the semicircular air grooves, the height of the water tank is lower than that of the semicircular air grooves, the water tank is fixed at the lower position of the semicircular air grooves, and a liquid falling hole is arranged on the liquid falling platform.

[0007] As preferred: the liquid falling platform is arranged below the bottom plate and also has a liquid falling platform extension section with the same size as the liquid falling platform, the extension section is spliced by a plurality of liquid blocking plates, and a buffer filler layer is arranged at the bottom of the extension section, and the extension section and the buffer filler layer prevent the water entering the liquid falling hole from splashing and falling rapidly.

[0008] The beneficial effects of the present application are as follows:

[0009] 1. The device of the present application reduces the influence of liquid surface fluctuation after the liquid amount in the liquid storage pool is extracted by using the liquid falling platform design. The liquid falling platform expansion plane can play a damping role in liquid fluctuation.

[0010] 2. The height difference design of the liquid falling platform and the bottom plate ensures the utilization of the liquid amount in the liquid storage pool.

[0011] 3. The long pipe as the liquid falling pipe design is cancelled, and a hole is directly arranged on the liquid falling platform, which avoids the occurrence of cross-section perfect contraction of the hole due to sharp edge and far away from the wall surface, causing unstable flow of liquid in the pipe, and further causing temporary flow interruption.

[0012] 4. After the liquid flows out of the hole on the platform, the buffer filler is arranged in the middle to buffer the falling liquid, so that the liquid enters the distributor or the filler more stably. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structure diagram of the existing long pipe guide type pre-distributor.

[0014] Figure 2 is a gas-liquid distribution diagram of the existing long pipe guide type pre-distributor.

[0015] Figure 3 is a structure diagram of the present application.

[0016] Figure 4 is a gas-liquid distribution diagram of the present application.

[0017] Figure 5 is a principle diagram of the present application.

[0018] Figure 6 is a principle diagram of the existing long pipe guide type pre-distributor. DETAILED DESCRIPTION

[0019] The present application will be described in detail below with reference to the drawings:Figure 3 As shown, a low-temperature anti-fluctuation tower liquid pre-distributor includes a distributor body 1, which is composed of a surrounding tube 2 and a bottom plate 3. Two ventilation grooves 4 are arranged in a semicircular shape and pass through the bottom plate inside the surrounding tube 1. A rectangular groove 5 is provided between the two semicircular ventilation grooves 4. The groove 5 is provided with a liquid down-dropping device 6. The amount of liquid in the liquid storage tank is determined by adjusting the height of the liquid down-dropping device 6 in the middle. The liquid down-dropping device and the ventilation groove divide the surrounding tube 2 into an annular liquid storage tank 7. A liquid outlet 8 is also provided on one side wall of the surrounding tube 2.

[0020] The liquid descending device 6 is a liquid descending platform, which is a block-shaped water trough 9 arranged between two semicircular ventilation grooves 4. The two side edges of the water trough 9 are parallel to the two side edges of the two semicircular ventilation grooves 4. Its height is lower than the two side semicircular ventilation grooves 4. It is fixed in the lower middle position of the semicircular ventilation grooves 4 and is provided with a liquid descending hole 10 on the liquid descending platform.

[0021] The downcomer platform is located below the bottom plate 3 and is provided with a downcomer platform extension section 11 of the same size as the downcomer platform. The extension section 11 is composed of multiple liquid baffles 12, and a buffer filler layer 13 is placed at the bottom thereof. The extension section 11 and the buffer filler layer 13 prevent the water entering the downcomer hole 10 from splashing out and falling rapidly. For ease of understanding, the following is provided: Figure 4 Schematic diagram of gas-liquid distribution of the present invention.

[0022] The design principles of the present invention are as follows:

[0023] Nozzle free flow

[0024] Bernoulli equation - the dynamic equation for steady flow of an ideal fluid: when a fluid flows with viscous losses neglected, the sum of the pressure potential energy, kinetic energy, and potential energy between any two points on the streamline remains constant.

[0025]

[0026] Where P is the pressure at a point in the fluid, V is the velocity of the fluid at that point, ρ is the fluid density, g is the acceleration due to gravity, h is the height of the point, and C is a constant.

[0027] In summary, if Figure 5 As shown, for the two sections 1 and 2, the pressures are P0 and Pc respectively, the fluid flow rates are 0 and Vc respectively, the heights are hl and h2 respectively, p is the liquid density, g is the acceleration of gravity, and according to Bernoulli's conservation principle

[0028] It can be seen that for sections 1 and 2, the following conditions are satisfied:

[0029]

[0030] Again because:

[0031]

[0032] Get:

[0033]

[0034] Because the cross section 2 is a small hole, there is energy loss from cross section 1 to cross section 2, so Bernoulli's principle needs to be corrected, and a correction coefficient ξ needs to be added c

[0035]

[0036] From the velocity V1 to Vc exists small hole throttling, according to the principle of small hole throttling and the related data of chemical principle, and for sharp edge and far away from the wall hole, C-C cross section perfect contraction, sharp change orifice contraction coefficient ε≈0.63 is the experimental measurement value, orifice resistance coefficient ξ c 0.06, μ=0.82 is obtained.

[0037] Therefore, the formula is:

[0038]

[0039] Where μ is the dynamic viscosity of the liquid, and ε is the correction coefficient.

[0040] Long pipe free outflow

[0041] Figure 6 As shown, for saturated liquid, the liquid is vaporized due to vacuum, so that the vacuum of C-C cross section is destroyed, and the maximum is saturated pressure, so the orifice outflow can be calculated according to h', and the flow coefficient 0.82 is brought in to obtain the maximum liquid level above the orifice. Therefore, it can be judged that the flow in the pipe is unstable.

[0042] According to the above data, it can be seen that the device designed by the application reduces the influence of liquid level fluctuation after the liquid storage tank extracts liquid by using the liquid descending platform design, cancels the long guide pipe as the liquid descending pipe design, and changes to the direct hole on the liquid descending platform. The sharp edge and far away from the wall hole can be well avoided, the cross section perfect contraction is caused, the liquid flow in the pipe is unstable, and the short-term flow interruption occurs. And the liquid of the application falls after outflow from the platform hole, the buffer filler is arranged in the middle to buffer the falling liquid, so that the liquid enters the distributor or the filler more stably.

[0043] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited thereto, any change or replacement easily thought by those skilled in the art within the technical range disclosed by the application should be covered in the protection scope of the application.

Claims

1. A low-temperature anti-fluctuation tower liquid pre-distributor, comprising a distributor body, characterized in that: The distributor body is composed of a surrounding tube and a bottom plate. Two ventilation grooves are arranged in a semicircular shape and pass through the bottom plate inside the surrounding tube. A rectangular groove is provided between the two semicircular ventilation grooves. A liquid drop device is provided in the groove. The amount of liquid in the liquid storage tank is determined by adjusting the height of the liquid drop device in the middle. The liquid drop device and the ventilation groove divide the surrounding tube into an annular liquid storage tank. A liquid outlet is also provided on one side wall of the surrounding tube. The liquid drop device is a liquid drop platform, which is provided between the two semicircular ventilation grooves. The block water trough is parallel to the two side edges of the two semicircular ventilation grooves, and its height is lower than the semicircular ventilation grooves on both sides. It is fixed in the lower middle position of the semicircular ventilation grooves, and a downcomer hole is opened on the downcomer platform. The downcomer platform is located below the bottom plate and is also provided with a downcomer platform extension section of the same size as the downcomer platform. The extension section is composed of multiple liquid baffles, and a buffer filler layer is placed at the bottom thereof. The extension section and the buffer filler layer prevent water entering the downcomer hole from above from splashing out and falling quickly.

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