Separation and purification device for sodium alkali and potassium alkali industrial liquefied tail gas

Abstract

The utility model relates to the technical field of tail gas separation, in particular to a separation and purification device for liquefied tail gas in sodium alkali and potassium alkali industries. Comprising a dehydration device and a dechlorination device which are connected in sequence, the dehydration device is composed of more than two dehydration towers, the dechlorination device is composed of more than two dechlorination towers, and liquefied tail gas enters the dechlorination device for dechlorination after being dehydrated by the dehydration device. The dehydration device can be used for removing moisture in the tail gas, the dechlorination device can adsorb chlorine in the tail gas and then analyze the chlorine out, and through connection of various pipelines between the dehydration tower and the dechlorination tower, maximum energy utilization is achieved, and production cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to tail gas separation technical field, concretely is a kind of separation and purification device of sodium base and potassium base industrial liquefied tail gas. BACKGROUND

[0002] Liquefied tail gas is non-condensable gas discharged in chlorine liquefaction process in sodium base and potassium base industrial production, and the main treatment method at present has two kinds, one is to synthesize hydrogen chloride by using hydrogen and chlorine in liquefied tail gas, and the other is to prepare sodium hypochlorite by absorbing chlorine in liquefied tail gas through lye.These methods have certain advantages in recovery effect, energy consumption, equipment and investment cost, but also have shortcomings. ① synthesis of hydrogen chloride: liquefied tail gas and hydrogen are burned into synthesis furnace, and hydrogen chloride gas is synthesized, but the market demand of hydrogen chloride is less in recent years, so the economic benefit of the method of synthesizing hydrogen chloride is not high. ② preparation of sodium hypochlorite: liquefied tail gas is introduced into packed tower, and chlorine in liquefied tail gas is absorbed by spraying circulating lye to generate sodium hypochlorite product. In the circulation process of lye, pressurization and cooling are needed, and the energy consumption is high

[0003] And separating and purifying chlorine in liquefied tail gas is a new type of liquefied tail gas recycling method. The key to liquefied tail gas separation and purification is to select suitable separation process to realize the goals of high efficiency, safety, environmental protection and economy.

[0004] The main components of liquefied tail gas are chlorine, carbon dioxide, hydrogen, nitrogen and oxygen. The composition is relatively complex, and the separation is difficult. The pressure swing adsorption gas separation technology is to select effective solid adsorbent, and the target gas is adsorbed and regenerated by changing pressure. The regeneration speed of pressure swing adsorption is fast, and the energy consumption is low, which belongs to energy-saving gas separation technology. In view of the problems existing in liquefied tail gas separation and purification technology, it is an urgent problem to develop pressure swing adsorption device to separate and purify chlorine in liquefied tail gas. SUMMARY

[0005] In view of the above situation, in order to overcome the defects of the prior art, the utility model provides a kind of separation and purification device of sodium base and potassium base industrial liquefied tail gas to solve the problems involved in background art.

[0006] To achieve the above purpose, the utility model provides the following technical scheme: a kind of separation and purification device of sodium base and potassium base industrial liquefied tail gas, including dehydration device and dechlorination device connected in sequence, the dehydration device is made of two or more dehydration towers, the dechlorination device is made of two or more dechlorination towers, and liquefied tail gas enters dechlorination device after dehydration by dehydration device.

[0007] Further, the bottom of the dehydration tower is provided with a liquefied tail gas inlet and an impurity gas first outlet, and the top is provided with a filtered gas outlet, an impurity gas inlet and a dehydration tower communication port.

[0008] Further, the bottom of the dechlorination tower is provided with a filtered gas inlet and a product gas outlet, and the top is provided with an impurity gas second outlet and a dechlorination tower communication port.

[0009] Further, the impurity gas inlet of the dehydration tower is connected with the impurity gas second outlet of the dechlorination tower, the filtered gas outlet of the dehydration tower is connected with the filtered gas inlet of the dechlorination tower, each of the dehydration towers is connected through a dehydration tower communication port, and each of the dechlorination towers is connected through a dechlorination tower communication port.

[0010] Further, the liquefied tail gas inlet, the impurity gas first outlet, the filtered gas outlet, the impurity gas inlet, the dehydration tower communication port, the filtered gas inlet, the product gas outlet, the impurity gas second outlet and the dechlorination tower communication port are all provided with valves.

[0011] Further, the internal structures of the dehydration tower and the dechlorination tower are same, comprising a shell, a gas distributor arranged at the bottom of the inner side of the shell, an adsorbent containing groove arranged above the gas distributor, and a heat exchanger arranged at the outer periphery of the adsorbent containing groove.

[0012] Further, the gas distributor is connected with the liquefied tail gas inlet or the filtered gas inlet.

[0013] Further, the heat exchanger comprises heat exchange pipelines arranged at the outer periphery of the adsorbent containing groove, and water inlets and outlets arranged at both ends of the heat exchange pipelines.

[0014] Further, the gas distributor comprises a plurality of annular pipelines arranged coaxially with diameters decreasing in sequence, a main pipeline connected with the annular pipelines, and injection pipelines arranged on the upper end faces of the annular pipelines, the ends of the injection pipelines are provided with nozzles, the included angles between each of the injection pipelines and the central axes of the annular pipelines are consistent, and the annular pipelines, the main pipeline and the injection pipelines are communicated.

[0015] Further, the outer side of the heat exchange pipeline is provided with spiral fins.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows:

[0017] The dehydration device can be used for removing water in tail gas, the dechlorination device can adsorb and then analyze chlorine in tail gas, through various pipeline connections between the dehydration tower and the dechlorination tower, the maximization of energy utilization is realized, and the production cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a connection structure schematic view of the embodiment of the present application;

[0019] Figure 2It is the internal structure schematic view of the dehydration tower and the dechlorination tower of the utility model embodiment;

[0020] Figure 3 It is the overhead schematic view of the gas distributor of the utility model embodiment;

[0021] Figure 4 It is the pipeline surface structure schematic view of the heat exchanger of the utility model embodiment;

[0022] In the figure,

[0023] Dehydration tower 1, liquefied tail gas inlet 11, impurity gas first outlet 12, filtered gas outlet 13, impurity gas inlet 14, dehydration tower communication port 15,

[0024] Dechlorination tower 2, filtered gas inlet 21, product gas outlet 22, impurity gas second outlet 23, dechlorination tower communication port 24,

[0025] Shell 3, gas distributor 4, circular ring pipeline 41, main pipeline 42, injection pipeline 43, adsorbent containing groove 5, heat exchanger 6, heat exchange pipeline 61, spiral fin 62. DETAILED DESCRIPTION

[0026] The technical scheme in the embodiments of the utility model will be described clearly and completely in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0027] Embodiment 1:

[0028] As shown in Figures 1-2 A sodium base and potassium base industrial liquefied tail gas separation and purification device, comprising dehydration device and dechlorination device connected in sequence, the dehydration device is composed of two or more dehydration towers 1, the dechlorination device is composed of two or more dechlorination towers 2, after the liquefied tail gas is dehydrated by the dehydration device, it enters the dechlorination device for dechlorination.

[0029] The bottom of the dehydration tower 1 is provided with a liquefied tail gas inlet 11 and an impurity gas first outlet 12, and the top is provided with a filtered gas outlet 13, an impurity gas inlet 14 and a dehydration tower communication port 15. The bottom of the dechlorination tower 2 is provided with a filtered gas inlet 21 and a product gas outlet 22, and the top is provided with an impurity gas second outlet 23 and a dechlorination tower communication port 24.

[0030] The impurity gas inlet 14 of the dehydration tower 1 and the impurity gas second outlet 23 of the dechlorination tower 2 are connected, the filtered gas outlet 13 of the dehydration tower 1 and the filtered gas inlet 21 of the dechlorination tower 2 are connected, the dehydration towers 2 are connected through the dehydration tower communication ports 15, and the dechlorination towers 2 are connected through the dechlorination tower communication ports 24. The liquefied tail gas inlet 11, the impurity gas first outlet 12, the filtered gas outlet 13, the impurity gas inlet 14, the dehydration tower communication port 15, the filtered gas inlet 21, the product gas outlet 22, the impurity gas second outlet 23 and the dechlorination tower communication port 24 are all provided with valves.

[0031] The internal structures of the dehydration tower 1 and the dechlorination tower 2 are the same, including a shell 3, a gas distributor 4 arranged at the bottom of the inner side of the shell 3, an adsorbent containing groove 5 arranged above the gas distributor 4, and a heat exchanger 6 arranged at the outer periphery of the adsorbent containing groove 5. The gas distributor 4 is connected with the liquefied tail gas inlet 11 or the filtered gas inlet 21. Different sizes of molecular sieve adsorbents are placed in the adsorbent containing groove 5.

[0032] 1. The dehydration process of the dehydration device includes the following steps:

[0033] (1) Adsorption process

[0034] The raw material gas with a pressure of 0.1-1.0 MpaG is first buffered in a raw material buffer tank after being adjusted by dry air, then enters the dehydration tower 1 through the liquefied tail gas inlet 11 after removing solid particles. Under the selective adsorption of the special adsorbent, H2O is adsorbed, and other gas components flow out from the filtered gas outlet 13 at the top of the tower and are transported to the dechlorination tower 2.

[0035] When the front of the mass transfer zone of H2O reaches the reserved section of the bed outlet, the liquefied tail gas inlet 11 and the filtered gas outlet 13 of the dehydration tower 1 are closed, and the adsorption is stopped. The adsorption bed starts to enter the regeneration process.

[0036] (2) Hot blowing process

[0037] After the adsorption process is completed, the breakthrough gas at the top of the dechlorination tower 2 is heated to 70-150℃ and is sent into the dehydration tower 1 in the reverse direction of the adsorption, is discharged from the impurity gas first outlet 12 at the bottom of the dehydration tower 1, and is sent into the process of the previous drying system.

[0038] (3) Cold blowing process

[0039] After the hot blowing process is completed, the normal temperature breakthrough gas at the top of the dechlorination tower 2 is sent into the dehydration tower 1 in the reverse direction of the adsorption, the temperature of the adsorption bed is reduced to normal temperature, and the gas is discharged from the impurity gas first outlet 12 at the bottom of the dehydration tower 1 and is sent into the process of the previous drying system.

[0040] After this process, the dehydration tower 1 has completed a complete "adsorption-regeneration" cycle, and is ready for the next adsorption.

[0041] 2. The dechlorination process of the dechlorination device comprises the following steps:

[0042] (1) Adsorption process

[0043] The dehydrated product gas with a pressure of 0.1-1.0 MPa G flows out of the filtered gas outlet 13 of the dehydration tower 1, and enters the dechlorination tower 2 through the filtered gas inlet 21 after temperature control by the heater.

[0044] Under the selective adsorption of the molecular sieve adsorbent, the Cl2 component is adsorbed, and the O2 and N2 gases flow out of the second impurity gas outlet 23 at the top of the tower as waste gas for subsequent treatment.

[0045] When the adsorption front (referred to as the adsorption front) of the mass transfer zone of the adsorbed impurities reaches the reserved section at the outlet of the bed, the filtered gas inlet 21 and the second impurity gas outlet 23 of the adsorption tower are closed, and the adsorption is stopped. The adsorption bed starts to enter the regeneration process.

[0046] (2) Equalization pressure reduction process

[0047] After the adsorption process is completed, the higher pressure gas in the tower is discharged into the other regenerated lower pressure dechlorination tower 2 along the adsorption direction through the dechlorination tower communication port 24. This process is not only a pressure reduction process, but also a process of recovering the effective gas in the dead space of the bed.

[0048] (3) Vacuumizing process

[0049] After the equalization process is completed, the dechlorination tower 2 is vacuumized against the adsorption direction, so that the adsorbed gas is completely desorbed and discharged through the product gas outlet 22. The extracted gas is cooled and then enters the tail gas buffer tank.

[0050] (4) Equalization pressure increase process

[0051] After the vacuumizing process is completed, the higher pressure effective gas in the dechlorination tower 2 from other regeneration processes is used to increase the pressure of the dechlorination tower 2 through the dechlorination tower communication port 24. This process corresponds to the equalization pressure reduction process, and is not only a pressure increase process, but also a process of recovering the effective gas in the dead space of the bed of the other tower to ensure the recovery rate of the gas.

[0052] After this process, the dechlorination tower 2 has completed a complete "adsorption-regeneration" cycle, and is ready for the next adsorption.

[0053] The pressure swing adsorption of the application is suitable for separation of chlorine in mixed gas, and is particularly suitable for separation and purification of chlorine in liquefaction tail gas in sodium alkali and potassium alkali industrial production, has simple process, high recovery rate and purity of chlorine, and good economic and environmental protection benefits.

[0054] Embodiment 2:

[0055] The same as embodiment 1 is not repeated, and the difference is that:

[0056] As shown in Figures 3-4 The heat exchanger 6 includes heat exchange pipelines 61 arranged on the outer circumferential side of the adsorbent containing groove 5, and water inlets and outlets arranged at both ends of the heat exchange pipelines 61. The outer side of the heat exchange pipelines 61 is provided with spiral fins 62, which can increase the contact area of the heat exchanger and the internal gas, and further increase the heat conduction efficiency. The gas distributor 4 includes a plurality of annular pipelines 41 with diameters gradually decreasing and coaxially arranged, a main pipeline 42 connected with the annular pipelines 41, and jet pipelines 43 arranged on the upper end surface of the annular pipelines 41. The jet pipelines 43 are provided with nozzles at the ends, the included angles between each jet pipeline 43 and the central axis of the annular pipeline 41 are consistent, and the annular pipeline 41, the main pipeline 42 and the jet pipeline 43 are communicated. The jet pipelines 43 can realize vortex jetting, and increase the jetting efficiency.

[0057] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A device for separating and purifying sodium and potassium alkaline industrial liquefied tail gas, characterized in that: The device comprises a dehydration device and a dechlorination device connected in sequence, the dehydration device is composed of two or more dehydration towers, the dechlorination device is composed of two or more dechlorination towers, and the liquefied tail gas is dehydrated by the dehydration device and then enters the dechlorination device for dechlorination.

2. The apparatus for separating and purifying sodium and potassium alkali industrial liquefied tail gas according to claim 1, characterized in that, The bottom of the dehydration tower is provided with a liquefied tail gas inlet and an impurity gas first outlet, and the top is provided with a filtered gas outlet, an impurity gas inlet and a dehydration tower communication port.

3. The apparatus for separating and purifying sodium and potassium alkali industrial liquefied tail gas according to claim 2, characterized in that: The bottom of the dechlorination tower is provided with a filtered gas inlet and a product gas outlet, and the top is provided with an impurity gas second outlet and a dechlorination tower communication port.

4. The apparatus for separating and purifying sodium and potassium alkaline industrial liquefied tail gas according to claim 3, characterized in that: The impurity gas inlet of the dehydration tower is connected with the impurity gas second outlet of the dechlorination tower, the filtered gas outlet of the dehydration tower is connected with the filtered gas inlet of the dechlorination tower, the dehydration towers are connected through the dehydration tower communication ports, and the dechlorination towers are connected through the dechlorination tower communication ports.

5. The apparatus for separating and purifying sodium and potassium alkali industrial liquefied tail gas according to claim 3, characterized in that: The liquefied tail gas inlet, the impurity gas first outlet, the filtered gas outlet, the impurity gas inlet, the dehydration tower communication port, the filtered gas inlet, the product gas outlet, the impurity gas second outlet and the dechlorination tower communication port are all provided with valves.

6. The apparatus for separating and purifying sodium and potassium alkali industrial liquefied tail gas according to claim 3, characterized in that: The internal structures of the dehydration tower and the dechlorination tower are the same, comprising a shell, a gas distributor arranged on the inner bottom of the shell, an adsorbent containing groove arranged above the gas distributor, and a heat exchanger arranged on the outer periphery of the adsorbent containing groove.

7. The apparatus for separating and purifying sodium and potassium alkaline industrial liquefied tail gas according to claim 6, characterized in that: The gas distributor is connected with the liquefied tail gas inlet or the filtered gas inlet.

8. The apparatus for separating and purifying sodium and potassium alkaline industrial liquefied tail gas according to claim 6, characterized in that: The heat exchanger comprises heat exchange pipelines arranged on the outer periphery of the adsorbent containing groove, water inlets and outlets arranged at both ends of the heat exchange pipelines.

9. The apparatus for separating and purifying sodium and potassium alkaline industrial liquefied tail gas according to claim 6, characterized in that: The gas distributor comprises a plurality of annular pipelines arranged coaxially with diameters decreasing in sequence, a main pipeline connected with the annular pipelines, and injection pipelines arranged on the upper end surfaces of the annular pipelines, the injection pipelines are provided with nozzles at the distal ends, the angles between the injection pipelines and the central axes of the annular pipelines are consistent, and the annular pipelines, the main pipeline and the injection pipelines are communicated.

10. The apparatus for separating and purifying sodium and potassium alkaline industrial liquefied tail gas according to claim 8, characterized in that: The outer side of the heat exchange pipeline is provided with spiral fins.

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