Double-flange liquid level meter closed flushing device of desulfurization system

Abstract

The utility model belongs to the technical field of double-flange liquid level meters, and particularly relates to a closed flushing device for a double-flange liquid level meter of a desulfurization system. The device comprises a venturi jet device, a mixing reactor and a pre-alkali-washing settling tank which are connected in sequence, a heavy component outlet in the bottom of the pre-alkali-washing settling tank is connected with the venturi jet device through a pipeline, and a first valve and an alkali-washing flowmeter are arranged on the pipeline; a double-flange liquid level meter is further arranged on the pre-alkali washing settling tank, the positive pressure side and the negative pressure side of the double-flange liquid level meter are communicated with the bottom and the top of the pre-alkali washing settling tank respectively, the positive pressure side of the double-flange liquid level meter is further connected with an inlet pipeline of the alkali washing flowmeter through a pipeline, and a second valve and a third valve are arranged on the pipeline. By modifying an existing device and utilizing potential energy in a whole process system to flush impurities blocked on the positive pressure side of the double-flange liquid level meter, the calibration and comparison work of the liquid level meter is reduced while accurate interface display is ensured, the labor intensity is reduced, and the safety of operators is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of double-flange liquid level gauges, and in particular relates to a closed flushing device for a double-flange liquid level gauge of a desulfurization system. Background Art

[0002] In the petrochemical industry, in order to ensure the quality and safety of liquefied gas, it needs to be desulfurized before use to remove sulfide impurities such as hydrogen sulfide and mercaptans. Common desulfurization processes include alkaline desulfurization processes, in which amine substances such as ethanolamine are generally used to react with hydrogen sulfide in the liquefied gas for preliminary desulfurization. However, after amine desulfurization, trace amounts of hydrogen sulfide and other acidic non-hydrocarbon compounds often remain in the liquefied gas. In order to prevent these acidic substances from affecting the desulfurization efficiency and catalyst activity in the subsequent mercaptan removal process, the liquefied gas is usually pre-treated with alkaline washing.

[0003] In the pre-alkali washing process, a settling tank is usually used as a settling and separation facility for liquefied gas and alkali solution, and a flange level gauge is used as an interface gauge. The alkali solution in the settling tank is reused in a self-circulating manner. Due to the acid-base neutralization reaction in the settling tank and the presence of a small amount of rich amine solution in the liquefied gas, the salts formed in the alkali solution will continue to increase, causing "impurities and salts to accumulate" on the positive pressure side of the double flange level gauge. When the temperature changes, it is very easy to cause the "interface position remote transmission" to continue to rise with the increase in temperature. "Distortion" phenomenon, resulting in inaccurate interface position display, affecting the pre-alkali washing treatment effect; in addition, the operating personnel need to frequently dismantle and inspect and calibrate the level gauge. Since the pre-alkali washing alkali solution contains a large amount of sulfide and has a strong pungent odor, it will cause serious harm to the health of the operating personnel and cause a certain degree of environmental pollution.

[0004] To solve the above problems, some devices use external high-pressure flushing equipment to flush impurities on the positive pressure side of the double flange level gauge into the container to achieve closed flushing. However, this solution adds pressurizing equipment, which increases investment and increases the difficulty of daily operation and maintenance, and requires the selection of suitable flushing media, the properties of which cannot affect normal production. Some other devices use non-contact level gauges such as radar level gauges or ultrasonic level gauges instead of double flange level gauges, which solves the problem of frequent disassembly and inspection on the basis of achieving interface measurement. However, radar level gauges or ultrasonic level gauges are relatively expensive, difficult to disassemble and repair on a daily basis, and have a high risk factor during operation. Utility Model Content

[0005] In view of the above deficiencies in the prior art, the purpose of the utility model is to provide a closed flushing device for a double-flange liquid level gauge in a desulfurization system. By modifying the existing device, the potential energy inside the entire process system is used to flush the impurities blocked on the positive pressure side of the double-flange liquid level gauge without the need for external energy. This ensures smooth pressure conduction of the pressure-conducting part of the interface level gauge, avoids inaccurate interface position display, and ensures the smooth operation of the pre-alkali washing sedimentation tank. At the same time, it reduces the on-site liquid level gauge calibration and comparison work, reduces labor intensity, and ensures the safety of operators.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] The desulfurization system double flange level gauge closed flushing device comprises a Venturi ejector, a mixing reactor and a pre-alkali washing settling tank connected in sequence, the top light component outlet of the pre-alkali washing settling tank is connected to the extraction device through a pipeline, and the bottom heavy component outlet of the pre-alkali washing settling tank is connected to the Venturi ejector through a pipeline, and a No. 1 valve and an alkali washing flowmeter are arranged on the pipeline for controlling the flow of alkali solution; the pre-alkali washing settling tank is also provided with a double flange level gauge for measuring the liquid level in the pre-alkali washing settling tank; the positive pressure side and the negative pressure side of the double flange level gauge are respectively connected to the bottom and the top of the pre-alkali washing settling tank, so as to accurately reflect the liquid level changes in the tank; the positive pressure side of the double flange level gauge is also connected to the inlet pipeline of the alkali washing flowmeter through a pipeline, and a No. 2 valve and a No. 3 valve are arranged on the pipeline, and the No. 2 valve and the No. 3 valve are opened to realize the change of the flow path of the alkali solution and the control of the flow rate, thereby realizing the closed flushing of the impurities blocked on the positive pressure side.

[0008] The inlet of the Venturi ejector is connected to a liquefied gas delivery pump.

[0009] It also includes a venturi ejector bypass pipeline, the inlet and outlet of the venturi ejector bypass pipeline are respectively connected to the inlet and outlet of the venturi ejector.

[0010] The invention also comprises a mixing reactor bypass pipeline, wherein the inlet and the outlet of the mixing reactor bypass pipeline are respectively connected to the inlet and the outlet of the mixing reactor.

[0011] The outlet of the venturi ejector bypass line is also connected to the inlet of the mixing reactor bypass line, which is used to maintain the continuous operation of the system when the equipment fails or is repaired, or to optimize the operating efficiency of the system under specific working conditions.

[0012] The positive pressure side and negative pressure side of the double flange level gauge are also respectively provided with a positive pressure root valve and a negative pressure root valve. When the double flange level gauge needs to be maintained or overhauled, these two valves can be closed to cut off the connection with the pre-alkali washing sedimentation tank to ensure the safety of the maintenance work.

[0013] The working principle of the device is as follows:

[0014] The liquefied gas delivered by the liquefied gas delivery pump is mixed with the alkali solution from the bottom of the pre-alkali washing settling tank in the venturi ejector, and then fully contacted and reacted in the mixing reactor, and then enters the pre-alkali washing settling tank for sedimentation and separation to remove hydrogen sulfide in the liquefied gas. The liquefied gas after pre-alkali washing is discharged from the light component outlet at the top of the pre-alkali washing settling tank and enters the extraction device. The No. 1 valve that controls the circulation of the alkali solution in the pre-alkali washing settling tank is shut down regularly, and the No. 2 and No. 3 valves that control the self-flushing process are opened. The pressure difference is used to make the impurities and salts deposited on the positive pressure side of the double flange level gauge circulate with the liquefied gas through the venturi ejector, thereby eliminating the abnormality of inaccurate display of the double flange level gauge.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0016] (1) The enclosed flushing device for the double flange level gauge of the desulfurization system described in the utility model is modified on the basis of the existing device, and uses the potential energy inside the entire process system to flush the impurities blocked on the positive pressure side of the double flange level gauge. No external energy is required, and the flushing operation is simple and easy, which solves the problem of frequent failure and fluctuation of the interface position;

[0017] (2) The closed flushing device for the double-flange level gauge of the desulfurization system described in the utility model reduces the problem of interface fluctuation, thereby reducing the on-site level gauge calibration and comparison work, effectively avoiding the problem of alkali liquid scalding and sulfide stimulation that may be caused by the on-site operators during the inspection and calibration, reducing the labor intensity while ensuring the health and safety of the operators;

[0018] (3) The enclosed flushing device of the double-flange level gauge of the desulfurization system described in the utility model ensures smooth pressure conduction of the pressure-conducting part of the level gauge, avoids inaccurate level display, ensures the smooth operation of the pre-alkali washing sedimentation tank, reduces the frequency of alkali solution replacement, and saves the treatment cost of hazardous waste alkali solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the closed flushing device of the double flange liquid level gauge of the desulfurization system described in the utility model;

[0020] In the figure: 1. Venturi ejector; 2. Mixing reactor; 3. Pre-alkali washing settling tank; 4. Light component outlet; 5. Heavy component outlet; 6. No. 1 valve; 7. Alkaline washing flow meter; 8. Double flange level gauge; 9. No. 2 valve; 10. No. 3 valve; 11. Liquefied gas delivery pump; 12. Venturi ejector bypass pipeline; 13. Mixing reactor bypass pipeline; 14. Positive pressure root valve; 15. Negative pressure root valve. DETAILED DESCRIPTION

[0021] In order to make the purpose and technical solution of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings.

[0022] Example 1

[0023] like Figure 1 As shown, the closed flushing device of the double flange level gauge of the desulfurization system comprises a venturi ejector 1, a mixing reactor 2 and a pre-alkali washing settling tank 3 which are connected in sequence, the top light component outlet 4 of the pre-alkali washing settling tank 3 is connected to the extraction device through a pipeline, the bottom heavy component outlet 5 of the pre-alkali washing settling tank 3 is connected to the venturi ejector 1 through a pipeline, and a No. 1 valve 6 and an alkali washing flowmeter 7 are arranged on the pipeline; the pre-alkali washing settling tank 3 is also provided with a double flange level gauge 8, the positive pressure side and the negative pressure side of the double flange level gauge 8 are respectively connected to the bottom and the top of the pre-alkali washing settling tank 3, the positive pressure side of the double flange level gauge 8 is also connected to the inlet pipeline of the alkali washing flowmeter 7 through a pipeline, and a No. 2 valve 9 and a No. 3 valve 10 are arranged on the pipeline.

[0024] The inlet of the Venturi ejector 1 is connected to a liquefied gas delivery pump 11 .

[0025] The venturi ejector bypass pipeline 12 is also included, and the inlet and outlet of the venturi ejector bypass pipeline 12 are respectively connected to the inlet and outlet of the venturi ejector 1 .

[0026] The mixing reactor bypass line 13 is also included, and the inlet and outlet of the mixing reactor bypass line 13 are connected to the inlet and outlet of the mixing reactor 2 respectively.

[0027] The outlet of the venturi ejector bypass line 12 is also connected to the inlet of the mixing reactor bypass line 13 .

[0028] The positive pressure side and negative pressure side of the double flange level gauge 8 are respectively provided with a positive pressure root valve 14 and a negative pressure root valve 15 .

[0029] When working, the specific steps are as follows:

[0030] The liquefied gas delivered by the liquefied gas delivery pump 11 and the alkali solution sucked through the venturi ejector 1 are mixed in the venturi ejector 1, and the mixing effect is enhanced by high-speed flow, providing conditions for the subsequent desulfurization reaction. Then it enters the mixing reactor 2, and the liquefied gas and the alkali solution are further mixed evenly to ensure that the two are fully in contact and react, thereby improving the desulfurization efficiency. After the mixed reaction, it enters the pre-alkali washing sedimentation tank 3 for sedimentation and separation. The heavy component will settle to the bottom of the tank and be discharged from the heavy component outlet 5, while the light component will rise to the top of the tank and be discharged from the light component outlet 4 to enter the subsequent extraction device for further processing. Control the boundary position of the alkali solution in the pre-alkali washing sedimentation tank 3 to prevent the liquefied gas after pre-alkali washing from carrying alkali. Regularly sample and analyze the concentration of the alkali solution in the pre-alkali washing sedimentation tank 3 to determine whether the alkali needs to be replaced.

[0031] In order to ensure that the double flange level gauge 8 displays accurately, it is necessary to close valve No. 1 6 regularly to interrupt the circulation of alkali solution in the pre-alkali washing sedimentation tank 3; at the same time, start the self-flushing process, open valve No. 2 9 and valve No. 3 10, and use the pressure difference to make the impurities and salts accumulated on the positive pressure side of the double flange level gauge 8 circulate together with the liquefied gas through the Venturi ejector 1, thereby effectively removing obstacles that cause abnormal display.

Claims

1. A closed flushing device for double flange level gauge of desulfurization system, characterized in that: The invention comprises a venturi ejector (1), a mixing reactor (2) and a pre-alkali washing settling tank (3) which are connected in sequence. The light component outlet (4) at the top of the pre-alkali washing settling tank (3) is connected to an extraction device through a pipeline, and the heavy component outlet (5) at the bottom of the pre-alkali washing settling tank (3) is connected to the venturi ejector (1) through a pipeline. A first valve (6) and an alkali washing flow meter (7) are arranged on the pipeline. The pre-alkali washing settling tank (3) is also provided with a double flange level gauge (8). The positive pressure side and the negative pressure side of the double flange level gauge (8) are respectively connected to the bottom and the top of the pre-alkali washing settling tank (3). The positive pressure side of the double flange level gauge (8) is also connected to the inlet pipeline of the alkali washing flow meter (7) through a pipeline. A second valve (9) and a third valve (10) are arranged on the pipeline.

2. The closed flushing device for double flange level gauge of desulfurization system according to claim 1 is characterized in that: The inlet of the Venturi ejector (1) is connected to the liquefied gas delivery pump (11).

3. The closed flushing device for double flange level gauge of desulfurization system according to claim 1 is characterized in that: It also comprises a venturi ejector bypass pipeline (12), the inlet and outlet of the venturi ejector bypass pipeline (12) are respectively connected to the inlet and outlet of the venturi ejector (1).

4. The closed flushing device for double flange level gauge of desulfurization system according to claim 3 is characterized in that: It also comprises a mixing reactor bypass line (13), the inlet and outlet of the mixing reactor bypass line (13) are respectively connected to the inlet and outlet of the mixing reactor (2).

5. The closed flushing device for double flange level gauge of desulfurization system according to claim 4 is characterized in that: The outlet of the venturi ejector bypass line (12) is also connected to the inlet of the mixing reactor bypass line (13).

6. The closed flushing device for double flange level gauge of desulfurization system according to claim 1 is characterized in that: The positive pressure side and negative pressure side of the double flange liquid level gauge (8) are also provided with a positive pressure root valve (14) and a negative pressure root valve (15) respectively.

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