Chlor-alkali device hydrogen washing system with acid-base property adjusting function

Abstract

The utility model relates to the technical field of hydrogen washing, in particular to a chlor-alkali device hydrogen washing system with an acid-base property adjusting function, which comprises a hydrogen washing tower, a neutralizing tank, a washing water circulating pump and a washing water cooler, the side wall of the lower part of the washing tower is provided with a hydrogen inlet, and the upper part of the washing tower is provided with a hydrogen outlet; a liquid discharging pipe for communication is arranged between the washing tank and the neutralizing tank, and the liquid level in the washing tower is higher than that of the washing tank; an acid inlet pipe and a water inlet pipe which are communicated with the interior of the neutralizing tank are arranged on the neutralizing tank, and a liquid outlet pipe used for being communicated with the washing water circulating pump is arranged on one side, far away from the acid inlet pipe and the water inlet pipe, of the neutralizing tank. The hydrogen washing tower has the effect of improving the scaling and blocking conditions of the filler, the cooler and the pipeline in the hydrogen washing tower.

Description

Technical Field

[0001] The present application relates to the technical field of hydrogen washing, and particularly to a hydrogen washing system for a chlor-alkali plant with an acid-base adjustment function. Background Art

[0002] The hydrogen in the chlor-alkali plant is generated by electrolyzing brine. Therefore, the temperature can generally reach above 60°C, and it contains impurities such as sodium hydroxide. Thus, it will cause corrosion to equipment, pipelines, etc. At the same time, these impurities will also adsorb on the walls of the equipment and pipelines, causing blockages and affecting the normal operation of the plant. Therefore, the hydrogen out of the electrolytic cell is generally washed first to remove impurities and achieve the purpose of cooling.

[0003] Since the wet hydrogen coming out of the electrolytic cell carries a lot of alkali mist, it will cause the pH of the washing water to continuously rise. After the pH rises, the sodium hydroxide in the washing water will react with calcium and magnesium ions. Coupled with the carbon dioxide in the water and the relatively high water temperature, etc., finally calcium carbonate, magnesium hydroxide and other precipitates will be formed, thus causing fouling and blockage of the packing in the washing tower, the cooler and the pipeline.

[0004] In view of the above related technologies, since the current hydrogen washing water system does not have the function of adjusting the acid-base, after using for a period of time, the packing, cooler and pipeline in the hydrogen washing tower will be fouled and blocked, thus affecting the normal production of the plant. Utility Model Content

[0005] In order to improve the fouling and blockage of the packing, cooler and pipeline in the hydrogen washing tower, the present application provides a hydrogen washing system for a chlor-alkali plant with an acid-base adjustment function.

[0006] The hydrogen washing system for a chlor-alkali plant with an acid-base adjustment function provided by the present application adopts the following technical solutions:

[0007] A hydrogen washing system for a chlor-alkali plant with an acid-base adjustment function includes a hydrogen washing tower, a neutralization tank, a washing water circulation pump and a washing water cooler. The washing tower is provided with a hydrogen inlet on the side wall of the lower part and a hydrogen outlet on the upper part. A downcomer for connection is provided between the washing tank and the neutralization tank. The liquid level in the washing tower is higher than the liquid level in the washing tank;

[0008] The neutralization tank is provided with an acid inlet pipe and a water inlet pipe communicating with the inside. The neutralization tank is provided with a liquid outlet pipe for connecting the washing water circulation pump on the side away from the acid inlet pipe and the water inlet pipe;

[0009] The washing water cooler is provided with a cold fluid inlet pipe, a hot fluid inlet pipe, a cold fluid outlet pipe and a hot fluid outlet pipe. One end of the hot fluid inlet pipe away from the washing water cooler is connected to the washing water circulation pump, and one end of the hot fluid outlet pipe away from the washing water cooler is connected to the hydrogen washing tower.

[0010] By adopting the above technical solution, the liquid level in the washing tower is higher than that in the neutralization tank. A certain level difference can ensure that the hydrogen washing water flows by gravity from the washing tower to the neutralization tank, preventing the occurrence of flooding in the tower. The hydrogen washing water is sent to the washing water cooler by the washing water circulation pump and cooled by the circulating water to reduce the temperature of the washing water, thereby reducing the formation of scale deposits such as calcium carbonate. The cooled washing water enters the washing tower to wash the hydrogen to remove the alkali mist entrained in the hydrogen and reduce the temperature. The washing water flowing to the bottom of the tower after washing then flows into the neutralization tank, where the sodium hydroxide in the washing water is neutralized and the calcium carbonate is dissolved by adding acid, thus avoiding the occurrence of scaling. At the same time, since the hydrogen washing tower and the connected pipelines are generally not acid-resistant, the use of an acid-resistant neutralization tank and adding acid in the neutralization tank can avoid the direct corrosion of the washing tower and the connected pipelines by acidic substances.

[0011] Furthermore, an exhaust pipe is provided on the neutralization tank.

[0012] By adopting the above technical solution, the exhaust pipe can discharge the carbon dioxide that may be generated after adding acid to prevent system overpressure. To prevent the escape of trace hydrogen contained in the washing water, the exhaust pipe can also be connected to the hydrogen exhaust main pipe for high-altitude venting.

[0013] Furthermore, a first regulating valve is provided on the acid inlet pipe, and a second regulating valve is provided on the water inlet pipe.

[0014] By adopting the above technical solution, the first regulating valve can automatically control the amount of acid added, and the second regulating valve can replenish water through remote control when the hydrogen washing water is insufficient.

[0015] Furthermore, a pH meter is provided on the hot fluid outlet pipe, and the pH meter is signal-connected to the first regulating valve for series control.

[0016] By adopting the above technical solution, the pH meter can monitor the pH value of the washing water. The first regulating valve is signal-connected to the pH meter, and the first regulating valve can automatically control the amount of acid added according to the monitored value of the pH of the washing water, thereby preventing the washing water from becoming acidic and corroding the system.

[0017] Furthermore, remote level gauges are provided on both the hydrogen washing tower and the neutralization tank.

[0018] By adopting the above technical solutions, the remote liquid level gauge on the hydrogen scrubbing tower can monitor the liquid level of the hydrogen scrubbing tower, avoiding the leakage of hydrogen through the vent of the neutralization tank when the liquid level is too low, and also avoiding flooding of the tower when the liquid level is too high. The remote liquid level gauge on the neutralization tank can monitor the liquid level of the neutralization tank, avoiding the idling of the washing water circulation pump and damage to the pump when the liquid level is too low, and also avoiding poor downward liquid flow when the liquid level is too high.

[0019] Furthermore, a sight glass for monitoring the liquid level is provided on the downward liquid pipe.

[0020] By adopting the above technical solutions, the sight glass on the downward liquid pipe can monitor the downward liquid condition, facilitating timely adjustment when the liquid level is too low or too high.

[0021] Furthermore, the number of the washing water circulation pumps is at least two.

[0022] By adopting the above technical solutions, at least two washing water circulation pumps are provided, one for operation and one for standby. When one of the washing water circulation pumps fails, it can be switched to the other pump for operation, thus ensuring the normal operation of the device.

[0023] Furthermore, cut-off valves are provided at the inlet and outlet positions of each of the washing water circulation pumps.

[0024] By adopting the above technical solutions, the cut-off valves are provided at the inlet and outlet positions of the two washing water circulation pumps. The setting of the cut-off valves can quickly control the switching of the operating pump body through remote operation, improving the convenience of operation.

[0025] Furthermore, an output pipe is connected and provided on the hot fluid input pipe, and an automatic regulating valve is provided on the output pipe.

[0026] By adopting the above technical solutions, the output pipe sends out the excess water generated during the hydrogen scrubbing process, and the automatic regulating valve is used to achieve automatic and stable regulation of the system liquid level, thereby ensuring the normal and stable operation of the device.

[0027] In summary, the present application includes at least one of the following beneficial technical effects:

[0028] 1. By neutralizing sodium hydroxide and dissolved calcium carbonate in the washing water, scale deposits such as calcium carbonate are avoided, preventing blockage of equipment, pipelines, etc. in the hydrogen scrubbing system.

[0029] 2. By externally connecting an acid-resistant neutralization tank, corrosion caused by acidic substances directly entering the hydrogen scrubbing tower and its pipelines is avoided;

[0030] 3. By serially controlling the first regulating valve on the acid addition pipe and the pH meter on the hot fluid output pipe, stable control of the acidity and alkalinity of the entire system is achieved, avoiding excessive acidity and alkalinity. Brief Description of the Drawings

[0031] Figure 1 FIG. is a schematic diagram of the overall structure of a hydrogen scrubbing system of a chlor-alkali plant with an acid-base adjustment function according to an embodiment of the present application.

[0032] Figure 2 FIG. is a schematic diagram of the structure of a hydrogen scrubbing tower according to an embodiment of the present application.

[0033] Figure 3 FIG. is a schematic diagram of the structure of a neutralization tank according to an embodiment of the present application.

[0034] Figure 4 FIG. is a schematic diagram of the structure of a wash water cooler according to an embodiment of the present application.

[0035] Figure 5 FIG. is a schematic diagram of the structure of a wash water circulation pump and a cut-off valve according to an embodiment of the present application.

[0036] Description of the reference numerals: 1, hydrogen scrubbing tower; 11, hydrogen inlet; 12, hydrogen outlet; 13, downcomer; 131, sight glass; 14, remote level gauge; 2, neutralization tank; 21, acid inlet pipe; 211, first regulating valve; 22, water inlet pipe; 221, second regulating valve; 23, outlet pipe; 24, exhaust pipe; 3, wash water circulation pump; 31, cut-off valve; 4, wash water cooler; 41, cold fluid inlet pipe; 42, hot fluid inlet pipe; 421, output pipe; 4211, automatic regulating valve; 43, cold fluid outlet pipe; 44, hot fluid outlet pipe; 441, pH meter. Detailed Description of the Embodiment

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the following further describes the present application in detail with reference to the Figures 1-5 accompanying drawings and embodiments.

[0038] An embodiment of the present application discloses a hydrogen scrubbing system of a chlor-alkali plant with an acid-base adjustment function. Referring to Figure 1 , the hydrogen scrubbing system of the chlor-alkali plant with an acid-base adjustment function includes a hydrogen scrubbing tower 1, a neutralization tank 2, a wash water circulation pump 3 and a wash water cooler 4.

[0039] Referring to Figure 1 and Figure 2 , the hydrogen scrubbing tower 1 is provided with a hydrogen inlet 11 on the side wall of the lower part and a hydrogen outlet 12 on the upper part. Hydrogen enters from the hydrogen inlet 11 and exits from the hydrogen outlet 12 in the hydrogen scrubbing tower 1 in a downward-inward and upward-outward manner. A downcomer 13 for connection is provided between the hydrogen scrubbing tower 1 and the neutralization tank 2, and an outlet pipe 23 for connection is provided between the neutralization tank 2 and the wash water circulation pump 3.

[0040] There is a certain liquid level difference between the liquid level in the hydrogen scrubber 1 and the liquid level in the neutralization tank 2. Through the gravity generated by the potential difference, the washing water in the scrubber can flow by gravity into the neutralization tank 2. In order to monitor the liquid discharge situation, a sight glass 131 is installed on the liquid discharge pipe 13.

[0041] Refer to Figure 1 and Figure 3 , in order to neutralize the sodium hydroxide absorbed during the washing process of the washing water, an acid inlet pipe 21 is provided on the neutralization tank 2. The sodium hydroxide in the washing water is neutralized by adding acid to prevent the formation of scale under alkaline conditions. At the same time, in order to facilitate the replenishment of washing water, a water inlet pipe 22 is provided on the neutralization tank 2, and the washing water can be replenished at any time.

[0042] Combined with Figure 2 , remote liquid level gauges 14 are provided on both the hydrogen scrubber 1 and the neutralization tank 2, which are respectively used to monitor the liquid levels in the hydrogen scrubber 1 and the neutralization tank 2, preventing the liquid levels in the hydrogen scrubber 1 and the neutralization tank 2 from being too high or too low, so as to avoid situations such as flooding the tower, hydrogen leakage or the pump running dry and burning out.

[0043] Refer to Figure 1 and Figure 4 , a cold fluid inlet pipe 41, a hot fluid inlet pipe 42, a cold fluid outlet pipe 43 and a hot fluid outlet pipe 44 are provided on the washing water cooler 4. The end of the hot fluid inlet pipe 42 far from the connection with the washing water cooler 4 is connected to the washing water circulation pump 3, and the end of the hot fluid outlet pipe 44 far from the connection with the washing water cooler 4 is connected to the hydrogen scrubber 1. The washing water is cooled by the cold fluid to achieve the purpose of temperature reduction, thereby reducing the formation of scale such as calcium carbonate.

[0044] Refer to Figure 3 , during the acid addition process, it is possible that the acid reacts with calcium carbonate to generate carbon dioxide, and a small amount of hydrogen in the washing water precipitates. In order to prevent gas accumulation and pressure increase, an exhaust pipe 24 for pressure relief is provided above the neutralization tank 2, and the exhaust pipe 24 can be connected to the hydrogen pressure relief main pipe.

[0045] Refer to Figure 1 , in order to prevent the acid from being added in excess or in insufficient amount, a first regulating valve 211 is provided on the acid inlet pipe 21, and a pH meter 441 is provided on the hot fluid outlet pipe 44. The pH meter 441 is signal-connected to the regulating valve and is in series control. When the pH meter 441 monitors an increase in the pH value, the first regulating valve 211 is opened wider; when the pH meter 441 monitors a decrease in the pH value, the first regulating valve 211 is closed smaller, so as to achieve the purpose of stably controlling the pH value. A second regulating valve 221 is provided on the water inlet pipe 22, and the automatic replenishment of the washing water can be realized at any time through remote control.

[0046] Refer to Figure 1 and Figure 5, an output pipe 421 is connected to the hot fluid input pipe 42, and an automatic regulating valve 4211 is provided on the output pipe 421, so as to output the washing water at any time. In order to prevent the washing water circulation pump 3 from malfunctioning and causing the system to shut down, two washing water circulation pumps 3 are provided in this embodiment, one is in operation and the other is in standby, and both can be remotely controlled to start and stop. Cut-off valves 31 are provided at the inlet and outlet positions of the two washing water circulation pumps 3, so as to realize the remote start, stop and switching of the washing water pumps.

[0047] The implementation principle of a hydrogen washing system of a chlor-alkali plant with an acid-base adjustment function in an embodiment of the present application is as follows: The hydrogen washing water is sent into the washing water cooler 4 by the washing water circulation pump 3 and is cooled by the circulating water, and the formation of scale deposits such as calcium carbonate is reduced by lowering the temperature of the washing water. The cooled washing water enters the washing tower to wash the hydrogen, remove the alkali mist entrained in the hydrogen and cool it down. The washing water flowing to the bottom of the tower then flows by gravity to the neutralization tank 2, where the sodium hydroxide in the washing water is neutralized and the calcium carbonate is dissolved by adding acid in the neutralization tank 2, so as to avoid scale formation. At the same time, since the hydrogen washing tower 1 and the connected pipelines are generally not acid-resistant, the acid-resistant neutralization tank 2 and adding acid in the neutralization tank 2 are adopted to avoid the direct corrosion of the washing tower and the connected pipelines by acidic substances.

[0048] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

[0049] In the description of this embodiment, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present application can be arranged in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

Claims

1. A hydrogen scrubbing system for a chlor-alkali plant with an acidity and alkalinity adjustment function, characterized in that: The invention comprises a hydrogen scrubbing tower (1), a neutralization tank (2), a scrubbing water circulation pump (3) and a scrubbing water cooler (4); the scrubbing tower is provided with a hydrogen inlet (11) on the side wall at the lower part and a hydrogen outlet (12) at the upper part; a lower liquid pipe (13) for communication is provided between the scrubbing tank and the neutralization tank (2); and the liquid level in the scrubbing tower is higher than the liquid level in the scrubbing tank; The neutralization tank (2) is provided with an acid inlet pipe (21) and a water inlet pipe (22) which are in communication with the interior thereof; the neutralization tank (2) is provided with a liquid outlet pipe (23) for communicating with the washing water circulation pump (3) on a side thereof which is away from the acid inlet pipe (21) and the water inlet pipe (22); The washing water cooler (4) is provided with a cold fluid input pipe (41), a hot fluid input pipe (42), a cold fluid output pipe (43) and a hot fluid output pipe (44); one end of the hot fluid input pipe (42) away from the washing water cooler (4) is connected to the washing water circulation pump (3); and one end of the hot fluid output pipe (44) away from the washing water cooler (4) is connected to the hydrogen washing tower (1).

2. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1 is characterized in that: An exhaust pipe (24) is provided on the neutralization tank (2).

3. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1, characterized in that: The acid inlet pipe (21) is provided with a first regulating valve (211), and the water inlet pipe (22) is provided with a second regulating valve (221).

4. The hydrogen scrubbing system for a chlor-alkali device with an acidity and alkalinity adjustment function according to claim 3 is characterized in that: The hot fluid output pipe (44) is provided with a pH meter (441), and a signal connection is established between the pH meter (441) and the first regulating valve (211) for series control.

5. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1, characterized in that: The hydrogen scrubbing tower (1) and the neutralization tank (2) are both provided with remote liquid level gauges (14).

6. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1, characterized in that: The lower liquid pipe (13) is provided with a sight glass (131) for monitoring the liquid level.

7. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1, characterized in that: The number of the washing water circulation pumps (3) is at least two.

8. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 7, characterized in that: Each of the washing water circulation pumps (3) is provided with a cut-off valve (31) at the inlet and outlet positions.

9. The hydrogen scrubbing system for a chlor-alkali device with acidity and alkalinity adjustment function according to claim 1, characterized in that: The hot fluid input pipe (42) is connected to an output pipe (421), and the output pipe (421) is provided with an automatic regulating valve (4211).

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