A hydrogen treatment system for a chlor-alkali plant

Abstract

The application discloses a hydrogen treatment system for a chlor-alkali device, the chlor-alkali device comprising a plurality of ion-exchange membrane electrolyzers, the hydrogen treatment system comprising a hydrogen washing tower, a hydrogen gas cabinet, a hydrogen cooler, a water mist catcher and a plurality of hydrogen compressor units connected in sequence, the inlet of the hydrogen washing tower being connected with the ion-exchange membrane electrolyzers, the outlet of the hydrogen washing tower being connected with the hydrogen gas cabinet, the outlet of the hydrogen gas cabinet being connected with the hydrogen cooler, the outlet of the hydrogen cooler being connected with the water mist catcher, the outlet of the water mist catcher being connected with each hydrogen compressor unit through a collecting pipe, and the outlet of each hydrogen compressor unit being connected with a downstream device through a pipeline. The hydrogen cooler, the catcher and the like are combined into one from a plurality of devices, related processes are concentratedly treated, equipment investment cost is reduced, and equipment maintenance cost in the later period is reduced; when the downstream device produces abnormally, hydrogen can be temporarily stored in the gas cabinet, and chlor-alkali device production is stabilized and is not affected by the downstream device.

Description

TECHNICAL FIELD

[0001] The present application relates to chemical plant technology, and particularly relates to a hydrogen treatment system for a chlor-alkali plant. BACKGROUND

[0002] Chlor-alkali, namely chlor-alkali industry, also refers to a method for producing chlorine, hydrogen and caustic soda by using saturated brine. In industry, NaOH, Cl2 and H2 are produced by electrolyzing saturated NaCl solution, and a series of chemical products are produced by using them as raw materials, which is called chlor-alkali industry. The chlor-alkali industry is one of the most basic chemical industries, and its products are widely used in chemical industry itself, light industry, textile industry, metallurgical industry, petroleum chemical industry and public utilities. In recent years, the chlor-alkali industry has developed rapidly, and most production plants have an annual output of not less than one million tons. Influenced by the scale of ion membrane electrolytic cell equipment, the most reasonable and energy-saving output of a single chlor-alkali is only 200,000 tons / year, and a large amount of hydrogen is produced. The by-product hydrogen produced in the chlor-alkali industry is applied in many places in the downstream, such as hydrogenation, hydrogen peroxide, cyclohexanone and other devices, but the hydrogen required by each device in the downstream is different in pressure and purity, which leads to differences in the process and equipment of the hydrogen treatment system, and the hydrogen treatment systems cannot be used as backup for each other, especially the hydrogen compressor system, which causes the increase of construction cost, energy waste and production hazards. SUMMARY

[0003] The present application aims to provide a method for integrating a by-product hydrogen treatment system of chlor-alkali industry.

[0004] Technical scheme: the hydrogen treatment system of the chlor-alkali plant provided by the present application comprises a plurality of ion membrane electrolytic cells, and the hydrogen treatment system comprises a hydrogen washing tower, a hydrogen gas cabinet, a hydrogen cooler, a water mist catcher and a plurality of hydrogen compressor units connected in sequence. The inlet of the hydrogen washing tower is connected with the ion membrane electrolytic cell, the outlet of the hydrogen washing tower is connected with the hydrogen gas cabinet, the outlet of the hydrogen gas cabinet is connected with the hydrogen cooler, the outlet of the hydrogen cooler is connected with the water mist catcher, the outlet of the water mist catcher is connected with each hydrogen compressor unit through a collecting pipe, and the outlet of each hydrogen compressor unit is connected with a downstream device through a pipeline.

[0005] The wet hydrogen produced by a plurality of ion membrane electrolytic cells enters the hydrogen washing tower, is washed and then enters the hydrogen gas cabinet, and the outlet of the hydrogen gas cabinet is connected with the hydrogen cooler. The cooling medium of the hydrogen cooler is chilled water, which cools the hydrogen to below 40 DEG C to condense the water vapor in the hydrogen. The outlet of the hydrogen cooler is connected with the water mist catcher, the condensed mist water in the cooled hydrogen is filtered out by the filter screen of the water mist catcher and discharged, the outlet of the water mist catcher is connected with the collecting pipe, the collecting pipe branches to each hydrogen compressor unit, a filter and a check valve are arranged in the inlet pipeline of each hydrogen compressor unit, the outlet of the hydrogen compressor is connected with a cooler, and the cooled hydrogen is delivered to each downstream device through a pipeline.

[0006] Further, several ion-exchange membrane electrolyzers are connected with one hydrogen washing tower through a collecting pipe. The wet hydrogen produced from multiple sets of ion-exchange membrane electrolyzers is collected into one pipeline through the collecting pipe, and the wet hydrogen enters the hydrogen washing tower.

[0007] Further, each ion-exchange membrane electrolyzer is connected with one hydrogen washing tower, and several hydrogen washing towers are connected with a hydrogen gas cabinet through a collecting pipe. The wet hydrogen produced from each set of ion-exchange membrane electrolyzer enters the hydrogen washing tower, the outlet of the hydrogen washing tower is connected with the collecting pipe to collect into one pipeline, and the hydrogen pipeline is connected with the hydrogen gas cabinet.

[0008] Further, the inlet of the hydrogen compressor unit is provided with a filter and a check valve, the outlet of the hydrogen compressor unit is connected with a cooler, the outlet of the cooler is sequentially provided with a deoxidizer and an adsorber, and the outlet of the adsorber is connected with a downstream device through a pipeline. The deoxidizer and the adsorber remove oxygen and impurities in the hydrogen to improve the purity of the hydrogen, and the hydrogen is transported to the downstream device through the outlet pipeline of the adsorber.

[0009] Preferably, the hydrogen gas cabinet is a large buffer tank with an automatically adjusted volume according to pressure, which is used as a temporary storage container to collect and temporarily store the hydrogen produced from multiple sets of electrolyzers.

[0010] Further, a hydrogen distribution platform is arranged between the hydrogen washing tower and the hydrogen gas cabinet. The outlet of the hydrogen washing tower is connected with the hydrogen distribution platform, and the outlet of the hydrogen distribution platform is connected with the hydrogen gas cabinet. The hydrogen distribution platform controls the pressure and flow rate of the hydrogen to prevent the hydrogen from flowing too fast to cause accidents caused by static electricity.

[0011] Preferably, the hydrogen washing tower is a packed tower, the hydrogen inlet is located at the bottom of the tower, and a circulating washing pump is further arranged at the bottom of the hydrogen washing tower. The outlet of the circulating washing pump is connected with a spraying pipe at the top of the hydrogen washing tower, the washing water flows down from the top of the tower, fully contacts with the hydrogen, and removes the residual salt, alkali and other impurities in the hydrogen and reduces the temperature.

[0012] Preferably, each hydrogen compressor unit includes a low-pressure hydrogen compressor and a high-pressure hydrogen compressor which are used as backup for each other. The hydrogen is pressurized and transported according to the required pressure and flow rate of the downstream user.

[0013] Further, several hydrogen compressor units are used as backup for each other, the outlet of each hydrogen compressor unit is connected with a pipeline and a double stop valve, a pressure gauge is arranged after the double stop valve, and the stop valve is used to reduce the pressure to achieve the backup of each unit.

[0014] Preferably, the deoxidizer and the adsorber are provided with a secondary line pipeline, and a secondary line valve is arranged on the secondary line pipeline to cut off the use of the deoxidizer and the adsorber.

[0015] Beneficial effects: compared with the prior art, the present application has the following advantages: 1. The hydrogen cooler, trap and the like are combined into one unit in the present application, related processes are concentrated, equipment investment cost is reduced, and equipment maintenance cost in later period is reduced; 2. The hydrogen gas tank is arranged in the present application, when downstream devices produce abnormally, hydrogen can be temporarily stored in the tank, and the production of chlor-alkali devices is stabilized and is not affected by downstream devices; 3. Each hydrogen compressor unit in the present application is a backup for each other, and the hydrogen compressors in each hydrogen compressor unit are backups for each other, when the low-pressure hydrogen compressor appears abnormal, the high-pressure hydrogen compressor can ensure the hydrogen consumption of downstream devices through pressure reduction, and the production of downstream devices is not affected by hydrogen compressor failure; 4. The hydrogen purification system can be used according to the hydrogen purity required by downstream devices, and the hydrogen required by downstream devices is met under the condition of energy saving; 5. The present application can be selected according to the scale of the device, the investment cost of the hydrogen washing tower and the site conditions, whether to collect at the outlet of the ion-exchange membrane electrolytic cell or at the outlet of the hydrogen washing tower. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Fig. 1 is a structural schematic diagram of a hydrogen compressor unit;

[0017] Figure 2 Fig. 2 is a structural schematic diagram of one embodiment of the present application;

[0018] Figure 3 Fig. 3 is a structural schematic diagram of another embodiment of the present application. DETAILED DESCRIPTION

[0019] The present application will be further described below in combination with the drawings.

[0020] The hydrogen treatment system for chlor-alkali devices provided by the present application, the chlor-alkali devices include a plurality of ion-exchange membrane electrolytic cells, the hydrogen treatment system includes a hydrogen washing tower 2, a hydrogen gas tank 5, a hydrogen cooler 7, a water mist trap 8 and three hydrogen compressor units 10 connected in sequence, the inlet of the hydrogen washing tower is connected with the ion-exchange membrane electrolytic cell, the hydrogen washing tower is connected with the hydrogen gas tank through a hydrogen distribution table, the outlet of the hydrogen gas tank is connected with the hydrogen cooler, the outlet of the hydrogen cooler is connected with the water mist trap, and the outlet of the water mist trap is connected with each hydrogen compressor unit through a collecting pipe. Preferably, the hydrogen washing tower is a packed tower, the hydrogen inlet is located at the bottom of the tower, and a circulating washing pump is further arranged at the bottom of the hydrogen washing tower, the outlet of the circulating washing pump is connected with a spraying pipe at the top of the hydrogen washing tower, and washing water flows down from the top of the tower. Preferably, the hydrogen gas tank is a large buffer tank with an automatically adjusted volume according to pressure.

[0021] As Figure 1As shown, the three hydrogen compressor units serve as backup units for each other. Each hydrogen compressor unit includes a low-pressure hydrogen compressor and a high-pressure hydrogen compressor, which serve as backups for each other. Each hydrogen compressor unit has a filter 104 and a check valve 105 at its inlet. Each hydrogen compressor unit's outlet is connected to a cooler 106. The cooler's outlet is connected via a pipeline and a double shut-off valve. A pressure gauge 108 is installed after the double shut-off valve, followed by a deoxygenator 11 and an adsorber 12. The double shut-off valve consists of valves 101, 102, 103, and 107. The outlet of the adsorber 12 is connected to a downstream unit via a pipeline. Both the deoxygenator 11 and the adsorber 12 have auxiliary pipelines. The auxiliary pipeline of the deoxygenator 11 has an auxiliary valve 111, and the auxiliary pipeline of the adsorber 12 has an adsorber auxiliary valve 121.

[0022] Example 1

[0023] like Figure 2 As shown, the hydrogen treatment system for a chlor-alkali plant according to the present invention includes three ion-exchange membrane electrolyzers 13. The wet hydrogen produced by the three ion-exchange membrane electrolyzers is collected into a pipeline through a first collecting pipe 1. The wet hydrogen enters a hydrogen scrubbing tower 2. A circulating scrubbing pump 3 is installed at the bottom of the hydrogen scrubbing tower 2. The outlet of the circulating scrubbing pump 3 is connected to a spray pipe at the top of the hydrogen scrubbing tower 2. The outlet at the top of the hydrogen scrubbing tower 2 is connected to a hydrogen distribution platform 4. The outlet of the hydrogen distribution platform 4 is connected to a hydrogen gas holder 5. The outlet of the hydrogen gas holder 5 is connected to a hydrogen cooler 6. The outlet of the hydrogen cooler 6 is connected to a water mist collector 8. The outlet of the water mist collector 8 is connected to a second collecting pipe 9. The second collecting pipe 9 branches to each hydrogen compressor unit 10. Each hydrogen compressor unit 10 inlet pipeline is equipped with a check valve 105 and a filter 104. After cooling, the hydrogen compressor unit 10 outlet is connected to a cooler 106 and then transported to downstream units 14 for use.

[0024] Example 2

[0025] like Figure 3 As shown, the hydrogen treatment system for a chlor-alkali plant according to the present invention includes three ion-exchange membrane electrolyzers 13. Each ion-exchange membrane electrolyzer is connected to a hydrogen scrubbing tower 2. The produced wet hydrogen enters the hydrogen scrubbing tower 2. A circulating scrubbing pump 3 is installed at the bottom of the hydrogen scrubbing tower 2. The outlet of the circulating scrubbing pump 3 is connected to the spray pipe at the top of the hydrogen scrubbing tower 2. The outlets at the top of the three hydrogen scrubbing towers 2 are connected to a first collecting pipe 1 and converge into a pipeline. The hydrogen pipeline is connected to a hydrogen distribution platform 4. The outlet of the hydrogen distribution platform 4 is connected to a hydrogen gas holder 5. The outlet of the hydrogen gas holder 5 is connected to a hydrogen cooler 7. The outlet of the hydrogen cooler 7 is connected to a water mist collector 8. The outlet of the water mist collector 8 is connected to a second collecting pipe 9. The second collecting pipe 9 branches to each hydrogen compressor unit 10. Each hydrogen compressor unit 10 inlet pipeline is equipped with a check valve 105 and a filter 104. After cooling, the hydrogen compressor unit 10 outlet is connected to a cooler 106 and then transported to downstream units for use via pipeline.

Claims

1. A hydrogen treatment system for a chlor-alkali plant comprising a number of ion-exchange membrane electrolyzers, characterized in that, The hydrogen treatment system comprises a hydrogen washing tower (2), a hydrogen gas cabinet (5), a hydrogen cooler (7), a water mist catcher (8) and a plurality of hydrogen compressor units (10) connected in sequence, the inlet of the hydrogen washing tower is connected with an ion-exchange membrane electrolyzer, the outlet of the hydrogen washing tower is connected with the hydrogen gas cabinet, the outlet of the hydrogen gas cabinet is connected with the hydrogen cooler, the outlet of the hydrogen cooler is connected with the water mist catcher, and the outlet of the water mist catcher is connected with each hydrogen compressor unit through a collecting pipe. The inlet of each hydrogen compressor unit is provided with a filter and a check valve, the outlet of the hydrogen compressor unit is connected with a cooler, the outlet of the cooler is provided with a deoxidizer and an adsorber in sequence, and the outlet of the adsorber is connected with a downstream device through a pipeline.

2. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, A plurality of ion-exchange membrane electrolyzers are connected with one hydrogen washing tower through a collecting pipe.

3. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, Each ion-exchange membrane electrolyzer is connected with one hydrogen washing tower, and a plurality of hydrogen washing towers are connected with the hydrogen gas cabinet through a collecting pipe.

4. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, The hydrogen gas cabinet is a large buffer tank with an automatically adjusted volume according to pressure.

5. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, A hydrogen distribution platform is arranged between the hydrogen washing tower and the hydrogen gas cabinet.

6. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, The hydrogen washing tower is a packed tower, the hydrogen inlet is located at the bottom of the tower, a circulating washing pump is further arranged at the bottom of the hydrogen washing tower, the outlet of the circulating washing pump is connected with a spraying pipe at the top of the hydrogen washing tower, and washing water flows down from the top of the tower.

7. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, Each hydrogen compressor unit comprises a low-pressure hydrogen compressor and a high-pressure hydrogen compressor which are used as backup for each other.

8. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, A plurality of hydrogen compressor units are backup units for each other, the outlet of each hydrogen compressor unit is connected with a pipeline and a double stop valve, and a pressure gauge is arranged after the double stop valve.

9. The hydrogen treatment system for a chlor-alkali apparatus according to claim 1, characterized by, The deoxidizer and the adsorber are both provided with a secondary line pipeline, and a secondary line valve is arranged on the secondary line pipeline.

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