Adsorption and desorption separation device for chlorine and oxygen in mixed gas

Abstract

The utility model relates to the technical field of adsorption and desorption separation, in particular to an adsorption and desorption separation device for chlorine and oxygen in mixed gas. The device consists of more than two adsorption towers, adsorption beds are arranged in the adsorption towers, and adsorbents are arranged in the adsorption beds; a mixed gas inlet and a chlorine outlet are formed in the tower bottom of each adsorption tower, an oxygen outlet is formed in the tower top of each adsorption tower, and a communicating pipeline group is further arranged between the two adsorption towers and is used for balancing the internal pressure of the two adsorption towers. The device adopts a special molecular sieve adsorbent, is suitable for separation of chlorine and oxygen in mixed gas, is particularly suitable for separation and recovery of chlorine and oxygen in reaction mixed gas of chlorine prepared from hydrogen chloride and caustic soda liquefied tail gas, and is simple in process, high in recovery rate and purity of chlorine and oxygen, good in economic and environment-friendly benefits and suitable for industrial production. On the basis of the dynamic characteristics of the adsorption and desorption processes, a proper control strategy is designed to ensure the cyclic and stable operation of the separation process.

Description

Technical Field

[0001] The utility model relates to the technical field of adsorption and desorption separation, and particularly relates to an adsorption and desorption separation device for chlorine and oxygen in a mixed gas. Background Technique

[0002] Chlorine and oxygen are widely used in industrial production. However, the mixture of chlorine and oxygen poses safety hazards during storage, transportation, and application. Therefore, it is necessary to separate them. The key to separating chlorine and oxygen is to select a suitable separation process to achieve the goals of high efficiency, safety, environmental protection, and economy.

[0003] Currently, the traditional separation of chlorine and oxygen mainly adopts methods such as cryogenic distillation, absorption, membrane separation, and adsorption. These methods have certain advantages in terms of separation effect, energy consumption, equipment, and investment cost, but they also have deficiencies.

[0004] ① Cryogenic distillation method: When the pressure of pure chlorine rises above 1 MPa, ordinary cooling water can be used to achieve the liquefaction and separation of chlorine. However, the energy consumption of gas compression is high, and the liquefied tail gas generated will result in a low chlorine recovery rate, and it is difficult to further efficiently separate oxygen.

[0005] ② Absorption method: An organic solvent is used to absorb the chlorine in the mixed gas at a lower temperature and higher pressure, and then desorbed at a higher temperature and lower pressure to obtain chlorine with a very high purity. In the cycle of absorption and desorption of this method, the organic solvent needs to be pressurized and the temperature changed, resulting in high energy consumption and solvent loss.

[0006] ③ Membrane separation method: Different gases are separated by using the different selective permeabilities of the membrane to different gases. The core of membrane separation is the membrane material, and the membrane material needs to comprehensively consider the selectivity, permeability, durability, and economy of chlorine. Currently, it is very difficult to achieve a gas purity of more than 95% for the permeate gas and the retentate gas separated by the membrane.

[0007] ④ Adsorption method: The separation is carried out by using the characteristic that adsorbents such as activated carbon have selective adsorption ability for chlorine or oxygen. Through the adsorption of the adsorbent, one of the gases is adsorbed, and then the other gas is desorbed from the adsorbent. This method is not safe with activated carbon and is prone to react with oxygen in the mixed gas at high temperatures.

[0008] In view of the problems existing in the chlorine and oxygen separation technology, there is an urgent need to separate chlorine and oxygen in the mixed gas at present. Summary of the Invention

[0009] In view of the above situation, in order to overcome the defects of the prior art, the present utility model provides an adsorption and desorption separation device for chlorine and oxygen in a mixed gas. By selecting a solid adsorbent and realizing the adsorption and regeneration of the target gas through the change of pressure, an energy-saving pressure swing adsorption device with a fast regeneration speed and low energy consumption is obtained.

[0010] To achieve the above object, the present utility model provides the following technical solutions:

[0011] An adsorption and desorption separation device for chlorine and oxygen in a mixed gas, which is composed of more than two adsorption towers. An adsorption bed is arranged in the adsorption tower, and an adsorbent is arranged in the adsorption bed;

[0012] A mixed gas inlet and a chlorine outlet are arranged at the bottom of the adsorption tower, and an oxygen outlet is arranged at the top of the adsorption tower.

[0013] A connecting pipeline group is also arranged between two adsorption towers, and the connecting pipeline group is used to balance the internal pressures of the two adsorption towers.

[0014] Further, there are two adsorption towers, including a first adsorption tower and a second adsorption tower.

[0015] Further, the connecting pipeline group includes a connecting pipeline arranged between the top of the first adsorption tower and the top of the second adsorption tower. A first valve is arranged at the connection of the connecting pipeline and the first adsorption tower, and a second valve is arranged at the connection of the connecting pipeline and the second adsorption tower.

[0016] Further, the adsorption tower includes a cylinder body, an upper head arranged at the upper end of the cylinder body, and a lower head arranged at the lower end of the cylinder body. An air outlet is arranged on the upper head, and an air inlet is arranged on the lower head;

[0017] A gas distribution device is arranged at the air inlet inside the cylinder body. The adsorption bed is arranged above the gas distribution device, a wire mesh is arranged above the adsorption bed, and a filter is arranged at the air outlet.

[0018] Further, a vacuum pump is arranged at the chlorine outlet.

[0019] Further, a mixed gas inlet valve, a chlorine outlet valve, and an oxygen outlet valve are respectively arranged on the mixed gas inlet, the chlorine outlet, and the oxygen outlet.

[0020] Further, the adsorbent is 13X molecular sieve.

[0021] Further, the pressure of the mixed gas entering from the mixed gas inlet is 0.1~1.2 MpaG.

[0022] Compared with the prior art, the beneficial effects of the present utility model are:

[0023] The utility model adopts a special molecular sieve adsorbent, which is applicable to the separation of chlorine and oxygen in a mixed gas, especially applicable to the separation and recovery of chlorine and oxygen in the reaction mixed gas of hydrogen chloride to chlorine and the tail gas of caustic soda liquefaction. The process is simple, and the recovery rate and purity of chlorine and oxygen are high, with good economic and environmental benefits. Based on the dynamic characteristics of the adsorption and desorption processes, a suitable control strategy is designed to ensure the stable operation of the separation process cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the connection structure of Embodiment 1 of the utility model;

[0025] Figure 2 It is a schematic diagram of the structure of the adsorption tower of Embodiment 1 of the utility model;

[0026] Figure 3 It is a schematic diagram of the connection structure of Embodiment 2 of the utility model;

[0027] In the figure:

[0028] The first adsorption tower 1, the second adsorption tower 2, the connecting pipeline 3, the first valve 4, the second valve 5, the mixed gas inlet 6, the chlorine outlet 7, the vacuum pump 8, the oxygen outlet 9, the third adsorption tower 10, the third valve 11, the mixed gas inlet valve 61, the chlorine outlet valve 71, the oxygen outlet valve 91,

[0029] The cylinder body 11, the upper head 12, the lower head 13, the air outlet 14, the air inlet 15, the gas distribution device 16, the adsorption bed 17, the wire mesh 18, the filter 19. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of the utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described embodiments are only a 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 of ordinary skill in the art without making creative efforts shall fall within the protection scope of the utility model. Embodiment

[0031] Consisting of Figure 1-2As shown in the figure, an adsorption and desorption separation device for chlorine and oxygen in a mixed gas consists of more than two adsorption towers. An adsorption bed 17 is provided inside the adsorption tower, and an adsorbent is provided inside the adsorption bed 17. A mixed gas inlet 6 and a chlorine outlet 7 are provided at the bottom of the adsorption tower. The pressure of the mixed gas entering from the mixed gas inlet 6 is 0.1~1.2 MpaG. A vacuum pump 8 is provided at the chlorine outlet 7. An oxygen outlet 9 is provided at the top of the adsorption tower. A mixed gas inlet valve 61, a chlorine outlet valve 71, and an oxygen outlet valve 91 are respectively provided on the mixed gas inlet 6, the chlorine outlet 7, and the oxygen outlet 9. A connecting pipe group is further provided between the two adsorption towers, and the connecting pipe group is used to balance the internal pressures of the two adsorption towers. There are two adsorption towers, including a first adsorption tower 1 and a second adsorption tower 2. The connecting pipe group includes a connecting pipe 3 provided between the top of the first adsorption tower 1 and the top of the second adsorption tower 2. A first valve 4 is provided at the connection of the connecting pipe 3 and the first adsorption tower 1, and a second valve 5 is provided at the connection of the connecting pipe 3 and the second adsorption tower 2.

[0032] The adsorption tower includes a cylinder body 11, an upper head 12 provided at the upper end of the cylinder body 11, and a lower head 13 provided at the lower end of the cylinder body 11. An air outlet 14 is provided on the upper head 12, and an air inlet 15 is provided on the lower head 13. A gas distribution device 16 is provided at the air inlet 15 inside the cylinder body 11. The adsorption bed 17 is provided above the gas distribution device 16. A wire mesh 18 is provided above the adsorption bed, and a filter 19 is provided at the air outlet 15. The adsorbent is 13X molecular sieve.

[0033] The separation device of the present application separates and recovers chlorine and oxygen from a mixed gas containing oxygen and chlorine (oxygen content 80~20%, chlorine content 20~80%, water content ≤5 ppm) by pressure swing adsorption, obtaining chlorine purity ≥90% and oxygen purity ≥98%, and the recovery rates of chlorine and oxygen both reach more than 98%. The separation and adsorption process is as follows:

[0034] (1) Adsorption process

[0035] The mixed gas of oxygen and chlorine with a pressure of 0.1~1.2 MPa·G, after being temperature-controlled by a heater, enters the first adsorption tower 1 from the mixed gas inlet 6. Under the selective adsorption of the molecular sieve adsorbent, chlorine is adsorbed in the bed layer, while oxygen is basically not adsorbed and directly passes through the bed layer and flows out from the oxygen outlet 9 at the top of the tower, and is transported to the subsequent process as a product.

[0036] When the mass transfer zone front of the adsorbed impurities reaches the reserved section at the outlet of the bed, close the mixed gas inlet valve 61 and the oxygen outlet valve 71 of the first adsorption tower 1 to stop adsorption. Open the first valve 4 of the first adsorption tower 1 and the second valve 5 of the second adsorption tower 2, and release the gas with a higher pressure in the first adsorption tower 1 into the second adsorption tower 2 with a lower pressure that has completed regeneration along the adsorption direction.

[0037] (2) Desorption process

[0038] After the adsorption process ends, open the chlorine outlet valve 71 of the chlorine outlet 7, close other valves, and turn on the vacuum pump 8 to evacuate the first adsorption tower 1 against the adsorption direction, so that the adsorbed gases such as chlorine are completely desorbed. The extracted gas is cooled and then enters the tail gas buffer tank to obtain product chlorine. At the same time, the second adsorption tower 2 completes the adsorption process.

[0039] (3) Pressure boosting process

[0040] After the desorption process is completed, open the first valve 4 of the first adsorption tower 1 and the second valve 5 of the second adsorption tower 2 to boost the pressure of the first adsorption tower 1 with the effective gas at a higher pressure in the second adsorption tower 2, recover the effective gas in the dead space of the bed of other towers, and improve the gas recovery rate.

[0041] After the pressure equalization and boosting process is completed, slowly and smoothly boost the pressure of the adsorption tower to the adsorption pressure with the product gas through the pressure boosting regulating valve, so that the first adsorption tower 1 can be smoothly switched to the next adsorption and ensure that the product purity does not fluctuate during this process.

[0042] The separation results of the separation device of this application are as follows:

[0043] Experimental conditions: mixed gas with 30% chlorine content, 70% oxygen content, water content ≤ 5 ppm, normal temperature, and 0.3 MPaG pressure; Experimental results: oxygen with a purity of 99%, chlorine with a purity of 92%, oxygen product yield of 98%, and chlorine product yield of 98%.

[0044] Experimental conditions: mixed gas with 40% chlorine content, 60% oxygen content, water content ≤ 5 ppm, normal temperature, and 0.5 MPaG pressure; Experimental results: oxygen with a purity of 98.5%, chlorine with a purity of 95%, oxygen product yield of 98.5%, and chlorine product yield of 98%.

[0045] Experimental conditions: mixed gas with 50% chlorine content, 50% oxygen content, water content ≤ 5 ppm, normal temperature, and 0.7 MPaG pressure; Experimental results: oxygen with a purity of 98%, chlorine with a purity of 96%, oxygen product yield of 99%, and chlorine product yield of 98%. Example

[0046] FromFigure 3 As shown, the same parts of this embodiment as those of Embodiment 1 will not be described in detail. The differences are as follows: There are three adsorption towers, including a first adsorption tower 1, a second adsorption tower 2, and a third adsorption tower 10. The connecting pipeline group includes a connecting pipeline 3 provided between the tops of the first adsorption tower 1, the second adsorption tower 2, and the third adsorption tower 10. A first valve 4 is provided at the connection of the connecting pipeline 3 and the first adsorption tower 1, a second valve 5 is provided at the connection of the connecting pipeline 3 and the second adsorption tower 2, and a third valve 11 is provided at the connection of the connecting pipeline 3 and the third adsorption tower 10. Multiple adsorption towers cooperate with each other to increase the separation efficiency.

[0047] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An adsorption and desorption separation device for chlorine and oxygen in a mixed gas, characterized in that: It consists of more than two adsorption towers. An adsorption bed is provided inside the adsorption tower, and an adsorbent is provided inside the adsorption bed; A mixed gas inlet and a chlorine gas outlet are provided at the bottom of the adsorption tower, and an oxygen outlet is provided at the top of the adsorption tower. A connecting pipeline group is also provided between the two adsorption towers, and the connecting pipeline group is used to balance the internal pressures of the two adsorption towers; There are two adsorption towers, including a first adsorption tower and a second adsorption tower; The connecting pipeline group includes a connecting pipeline between the top of the first adsorption tower and the top of the second adsorption tower. A first valve is provided at the connection of the connecting pipeline to the first adsorption tower, and a second valve is provided at the connection of the connecting pipeline to the second adsorption tower; the adsorbent is 13X molecular sieve.

2. The adsorption and desorption separation device for chlorine and oxygen in the mixed gas according to claim 1, wherein: The adsorption tower includes a cylinder body, an upper head provided at the upper end of the cylinder body, and a lower head provided at the lower end of the cylinder body. An air outlet is provided on the upper head, and an air inlet is provided on the lower head; A gas distribution device is provided at the air inlet inside the cylinder body. The adsorption bed is provided above the gas distribution device, a wire mesh is provided above the adsorption bed, and a filter is provided at the air outlet.

3. The adsorption and desorption separation device for chlorine and oxygen in the mixed gas according to claim 1, characterized in that: A vacuum pump is provided at the chlorine gas outlet.

4. The adsorption and desorption separation device for chlorine and oxygen in the mixed gas according to claim 1, wherein: A mixed gas inlet valve, a chlorine gas outlet valve, and an oxygen outlet valve are respectively provided on the mixed gas inlet, the chlorine gas outlet, and the oxygen outlet.

5. The adsorption and desorption separation device for chlorine and oxygen in the mixed gas according to claim 1, wherein: The pressure of the mixed gas entering from the mixed gas inlet is 0.1~1.2 MpaG.

Images