Economical, safe and reliable liquid level control system

Abstract

The utility model relates to an economical, safe and reliable liquid level control system which comprises a normal-pressure liquid container with a spraying mechanism inside, a control liquid level line is arranged in the normal-pressure liquid container, a floating ball valve group is arranged at the position of the control liquid level line, inlets of floating ball valves in the floating ball valve group are externally connected with an absorption liquid pipe liquid inlet pipeline, and the absorption liquid pipe liquid inlet pipeline is connected with an absorption liquid pipe liquid outlet pipeline. The bottom of the normal-pressure liquid container is provided with a transmissible pressure gauge and a rich liquid discharge port, the normal-pressure liquid container is connected with an unpurified gas inlet pipeline and an absorption agent liquid inlet pipeline, a gas inlet of the unpurified gas inlet pipeline is located above a control liquid level line, and a gas outlet of the absorption agent liquid inlet pipeline is located above a control liquid level line; an overflow connector is arranged on the normal-pressure liquid container and located between a liquid level control line and an inlet horizontal line of the ball float valve, the overflow connector is connected with a U-shaped overflow elbow, the tail end of the overflow elbow is connected with an abnormal liquid drainage pipeline through a sight glass, and a first gate valve is arranged at the U-shaped bottom. Compared with the prior art, the liquid level stability is guaranteed, and meanwhile economy and safety are considered.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical waste gas spraying, in particular to the liquid level control of a spraying absorption tower for waste gases such as tail gas and relaxation gas. Background Art

[0002] Flue gas desulfurization in the petrochemical industry and tail gas containing volatile organic compounds such as acids, alkalis or solvents in the fine chemical industry all need to be pre-treated by spraying before being discharged or recycled. As for the liquid level control in the tower, almost all detection instruments are used to detect the liquid level of the absorption tower kettle, and then the detected liquid level value is used to control the opening of the regulating valve of the absorption liquid pipeline to adjust the liquid level of the tower kettle. The safety interlocking system used is generally as follows: high liquid level alarm, high-high liquid level cuts off the absorption liquid inlet regulating valve; low liquid level alarm, low-low liquid level stops the circulation pump at the bottom of the absorption liquid tower, and this set of instruments and corresponding supporting facilities require a large investment. In addition, for flue gas containing high dust, there will be a large amount of particulate matter in the absorption liquid. Generally, a double flange diaphragm differential pressure level gauge is used, but after a period of use, it needs to be manually flushed with fresh water, otherwise the measuring pipeline leading from the tower wall will be blocked, the instrument cannot read, and a safety risk will arise. Utility Model Content

[0003] In view of the above problems, the utility model proposes an economical, safe and reliable liquid level control system, which can stably control the liquid level while taking into account economy and safety.

[0004] To achieve the above objectives, the following technical scheme is adopted: an economical, safe and reliable liquid level control system, including a normal pressure liquid container with an internal spray mechanism, an absorption liquid inlet pipeline, an unpurified gas inlet pipeline, an absorption agent inlet pipeline, an overflow elbow, an external rich liquid discharge pipeline and an abnormal liquid discharge pipeline,

[0005] A control liquid level line is set in the normal pressure liquid container, and a float valve group is arranged at the position of the control liquid level line. The inlet of the float valve in the float valve group is externally connected to the absorption liquid pipe inlet pipeline, and the outlet is connected to the normal pressure liquid container.

[0006] A remote pressure gauge and a rich liquid discharge port are arranged at the bottom of the normal pressure liquid container, and the external rich liquid discharge pipeline is connected to the normal pressure liquid container through the rich liquid discharge port.

[0007] The raw gas inlet pipeline and the absorption agent inlet pipeline are both connected to the normal pressure liquid container, and the air inlet of the raw gas inlet pipeline is located above the control liquid level line.

[0008] The overflow elbow is U-shaped, connected to a normal-pressure liquid container, and its overflow interface with the normal-pressure liquid container is located between a control liquid level line and an inlet horizontal line of a float valve. The end of the overflow elbow is connected to an abnormal liquid discharge pipeline through a sight glass, and a first gate valve is provided at the U-shaped bottom of the overflow elbow.

[0009] Furthermore, the float valve group comprises at least three float valves, and a second gate valve is arranged at the front end of each float valve.

[0010] Furthermore, the difference between the horizontal elevation of the U-shaped opening of the overflow elbow and the horizontal elevation of the U-shaped bottom is at least 500 mm, and the diameter of the overflow elbow is greater than or equal to the diameter of the absorption liquid pipe inlet line.

[0011] Furthermore, the remote pressure gauge is set to alarm for a high pressure value.

[0012] Furthermore, the normal pressure liquid container is a spray absorption tower.

[0013] Beneficial effects of the utility model: the utility model observes the situation of the sight glass through the remote pressure gauge alarm, and achieves the purpose of controlling and adjusting the liquid level through the cooperation of the U-shaped overflow elbow and the float valve that can be independently controlled in parallel. Compared with the existing technology, it ensures the stability of the liquid level while taking into account economy and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of an embodiment of the present invention.

[0015] As shown in the figure: 1. Normal pressure liquid container; 2. Absorption liquid inlet pipeline; 3. Unpurified gas inlet pipeline; 4. Absorption agent inlet pipeline; 5. Overflow elbow; 6. External rich liquid discharge pipeline; 7. Abnormal liquid discharge pipeline; 8. Float valve; 9. Second gate valve; 10. Remote pressure gauge; 11. Sight glass; 12. First gate valve; 13. Water pump; 100. Spraying mechanism. DETAILED DESCRIPTION

[0016] Example 1

[0017] In the following, the technical scheme in the embodiment of the utility model will be clearly and completely described by taking alkali solution spraying flue gas desulfurization as an example in conjunction with the drawings in the embodiment of the utility model.

[0018] like Figure 1 The invention provides an economical, safe and reliable liquid level control system, comprising a normal pressure liquid container 1 with a spray mechanism 100 inside, an absorption liquid inlet pipeline 2, an unpurified gas inlet pipeline 3, an absorption agent inlet pipeline 4, an overflow elbow 5, an external rich liquid discharge pipeline 6 and an abnormal liquid discharge pipeline 7. The normal pressure liquid container 1 used in this example is a spray absorption tower, but the new normal pressure liquid container 1 is not limited to a spray absorption tower.

[0019] A control liquid level line is set in the normal pressure liquid container 1, and three float valves 8 are arranged at the position of the control liquid level line. The inlets of the three float valves 8 are all externally connected to the absorption liquid inlet pipeline 2, and the outlets are connected to the normal pressure liquid container 1. The front ends of the three float valves 8 are all provided with a second gate valve 9. A remote pressure gauge 10 and a rich liquid discharge port are arranged at the bottom of the normal pressure liquid container 1, and the remote pressure gauge 10 is provided with a high pressure value alarm.

[0020] The external rich liquid pipeline 6 is connected to the normal pressure liquid container 1 through the rich liquid discharge port, the raw gas inlet pipeline 3 and the absorption agent inlet pipeline 4 are both connected to the normal pressure liquid container 1, and the air inlet of the raw gas inlet pipeline 3 is located above the control liquid level line.

[0021] The overflow elbow 5 is U-shaped, and the overflow elbow 5 is connected to the normal pressure liquid container 1. The overflow interface between the overflow elbow 5 and the normal pressure liquid container 1 is located between the control liquid level line and the inlet horizontal line of the float valve 8. The end of the overflow elbow 5 is connected to the abnormal discharge pipeline 7 through the sight glass 11. The first gate valve 12 is arranged at the U-shaped bottom of the overflow elbow 5. The difference between the horizontal elevation of the U-shaped opening of the overflow elbow 5 and the horizontal elevation of the U-shaped bottom is at least 500mm. The diameter of the overflow elbow 5 is greater than or equal to the diameter of the absorption liquid pipe inlet pipeline 2.

[0022] The absorption liquid S1 enters the normal pressure liquid container 1 from the absorption liquid pipe inlet pipeline 2, and the absorption liquid S1 in this example is water; the unpurified flue gas or tail gas S2 enters the normal pressure liquid container 1 from the unpurified gas inlet pipeline 3, and the unpurified flue gas or tail gas S2 in this example is sulfur-containing unpurified flue gas; the absorption agent S3 enters the normal pressure liquid container 1 from the absorption agent inlet pipeline 4, and the absorption agent S3 in this example is alkali solution; the rich liquid S4 absorbed in the normal pressure liquid container 1 is discharged from the external rich liquid pipeline 6, and a water pump 13 can also be set at the discharge port of the normal pressure liquid container 1 to be connected to the pipeline of the spray mechanism 100 of the normal pressure liquid container 1 to return the absorbed rich liquid S4 to the spray mechanism 100, and the rich liquid S4 in this example is a neutralized salt-containing liquid; the abnormal drainage S5 of the normal pressure liquid container 1 is discharged from the abnormal drainage pipeline 7, and the so-called abnormal drainage is the overflow caused by the failure of the float valve 8.

[0023] The working principle of this implementation is:

[0024] As for the float valve 8, the probability of its failure still exists. In the case where only one float valve 8 is set, if the float valve 8 fails and cannot be closed or opened, it will bring great risks. The inability to close causes the liquid level in the normal pressure liquid container 1 to continue to rise, and there is a risk of flooding the container or blocking the flue gas inlet; in the case of failure to open, since the flue gas is a high-temperature gas, the purified flue gas will take away some water vapor, which will also cause the liquid level to continue to decrease, causing a risk of low liquid level. Set up multiple float valves 8 in parallel to inlet water. If the liquid level is low, the float will drop and multiple routes will open at the same time. It is unlikely that several float valves 8 will fail at the same time. As long as one route is open, water inlet can be guaranteed;

[0025] The disadvantage of setting multiple parallel float valves 8 is that as long as one float valve 8 fails and is in a continuously open state, there is a risk of high liquid level. For this reason, an overflow interface is set at a position between the control liquid level line of the pressurized liquid container 1 and the inlet horizontal line of the float valve 8, and an overflow elbow 5 and a sight glass 11 are set. A first gate valve 12 is set at the bottom of the overflow elbow 5. Water is passed through the first gate valve 12 at the initial start-up to form a water seal to ensure that smoke cannot pass through;

[0026] If there is liquid flowing out of the overflow interface all the time, it is obviously unfavorable, indicating that the float valve 8 has a fault. In order to find and solve the fault in time, a remote pressure gauge 10 is set at the bottom of the normal pressure liquid container 1, and a high pressure alarm is set. Then go to the sight glass 11 to observe whether there is liquid flow. After confirmation, close the second gate valve 9 in front of each float valve 8 one by one, and observe the liquid flow in the sight glass 11. If the liquid flow disappears, it means that the float valve 8 has a fault, and the corresponding second gate valve 9 can be closed. The corresponding second gate valves 9 of other float valves 8 are still open. The system can continue to operate normally and only wait for the next shutdown for maintenance.

[0027] Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Claims

1. An economical, safe and reliable liquid level control system, comprising a normal pressure liquid container (1) with a spray mechanism (100) inside, characterized in that: It also includes an absorption liquid inlet pipeline (2), an unpurified gas inlet pipeline (3), an absorption agent inlet pipeline (4), an overflow elbow (5), an external rich liquid discharge pipeline (6) and an abnormal liquid discharge pipeline (7). A control liquid level line is set in the normal pressure liquid container (1), and a float valve group is arranged at the position of the control liquid level line. The inlet of the float valve (8) in the float valve group is externally connected to the absorption liquid pipe inlet line (2), and the outlet is connected to the normal pressure liquid container (1). A remote pressure gauge (10) and a rich liquid discharge port are provided at the bottom of the normal pressure liquid container (1), and the external rich liquid discharge pipeline (6) is connected to the normal pressure liquid container (1) through the rich liquid discharge port. The unpurified gas inlet pipeline (3) and the absorption agent inlet pipeline (4) are both connected to the normal pressure liquid container (1), and the air inlet of the unpurified gas inlet pipeline (3) is located above the control liquid level line. The overflow elbow (5) is U-shaped and communicates with the normal pressure liquid container (1). The overflow interface between the overflow elbow and the normal pressure liquid container (1) is located between the control liquid level line and the inlet horizontal line of the float valve (8). The end of the overflow elbow (5) is connected to the abnormal discharge pipeline (7) through a sight glass (11). A first gate valve (12) is provided at the U-shaped bottom of the overflow elbow (5).

2. The liquid level control system according to claim 1, characterized in that: The float valve group comprises at least three float valves (8), and a second gate valve (9) is arranged at the front end of each float valve (8).

3. The liquid level control system according to claim 2, characterized in that: The difference between the horizontal elevation of the U-shaped opening of the overflow elbow (5) and the horizontal elevation of the U-shaped bottom is at least 500 mm, and the diameter of the overflow elbow (5) is greater than or equal to the diameter of the absorption liquid pipe inlet line (2).

4. The liquid level control system according to claim 3, characterized in that: The remote pressure gauge (10) is provided with a high pressure value alarm.

5. The liquid level control system according to any one of claims 1 to 4, characterized in that: The normal pressure liquid container (1) is a spray absorption tower.

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