Fireproof and evacuation-proof system for sump oil tank

Abstract

The utility model belongs to the technical field of petrochemical engineering, and particularly relates to a fire prevention and evacuation prevention system for a waste oil tank, which comprises the waste oil tank and a nitrogen pipeline, the tank top of the waste oil tank is connected with a gas phase outlet pipeline, the gas phase outlet pipeline is respectively connected with an emptying pipeline and a torch pipeline, and the emptying pipeline is provided with a flame arrester. The nitrogen pipeline is connected to the emptying pipeline, and a self-operated regulating valve is arranged on the nitrogen pipeline. According to the fire prevention and evacuation prevention system for the sump oil tank, the upper space in the sump oil tank can be controlled to be in a nitrogen protection state, and the nitrogen protection state of the sump oil tank is always kept by additionally arranging the nitrogen pipeline, the self-operated regulating valve and the flow limiting orifice plate on the sump oil tank. And the gas mixture cannot reach the ignition and explosion range when being discharged to a torch and the atmosphere. Meanwhile, the pressure of the sump oil tank is automatically supplemented by the self-operated regulating valve when the sump oil is conveyed, and the condition that the pump cannot dose after the negative pressure in the tank is achieved is prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of petrochemical industry, and in particular relates to a fire prevention and vacuum prevention system for a dirty oil tank. Background Art

[0002] The waste oil tank of a petrochemical plant is usually buried underground. It is a cylindrical container made of iron plates. It is used to store waste oil discharged from oil pipelines, pumps or other equipment, and is collected in the waste oil tank through waste oil pipelines. The waste oil tank is connected to a waste oil pump, which can send the waste oil in the waste oil tank back to other containers for refining.

[0003] The gas phase pressure of the waste oil tank of a petrochemical plant is generally designed to be discharged to the flare system for combustion treatment. In some cases, it needs to be discharged to the atmosphere because the mixture of hydrocarbons and air can easily form an explosive mixed gas. Even if the venting pipeline is raised to more than tens of meters and flame arresters are added, there is still a risk of fire in thunderstorms. Similarly, the waste oil pump in the waste oil tank is at risk of pumping out and mechanical seal friction catching fire when conveying waste oil. At present, there is a mixed gas of hydrocarbons, nitrogen, etc. in the space between the liquid surface and the top of the storage tank. The mixture of hydrocarbons and air can easily form an explosive mixed gas, which may catch fire or explode when encountering open flames or high temperatures. Similarly, the waste oil pump in the waste oil tank is at risk of pumping out and mechanical seal friction catching fire when conveying waste oil. Summary of the invention

[0004] In view of the defects of the prior art mentioned above, the purpose of the utility model is to provide a waste oil tank fire prevention and vacuum prevention system, which always keeps the waste oil tank in a nitrogen protection state.

[0005] The technical solution adopted by the utility model is: a waste oil tank fire prevention and vacuum prevention system, including a waste oil tank and a nitrogen pipeline, the tank top of the waste oil tank is connected to a gas phase outlet pipeline, the gas phase outlet pipeline is respectively connected to a venting pipeline and a flare pipeline, a flame arrester is arranged on the venting pipeline, the nitrogen pipeline is connected to the venting pipeline, and a self-operated regulating valve is arranged on the nitrogen pipeline.

[0006] Furthermore, a shower valve is provided at a low point of the nitrogen pipeline.

[0007] Furthermore, the front path of the self-operated regulating valve is connected to a Y-type filter, and the rear path of the self-operated regulating valve is connected to a flow limiting orifice plate.

[0008] Furthermore, a pressure gauge and a pressure gauge valve are arranged behind the self-operated regulating valve.

[0009] Further, the front and rear paths of the self-operated regulating valve are provided with a front valve and a rear valve respectively. Further, the front valve, the self-operated regulating valve and the rear valve form a three-valve group, the three-valve group is provided with a secondary line, and the secondary line is connected to a secondary line valve.

[0010] Furthermore, an 8-shaped blind plate and a one-way valve are provided at the rear of the three-valve group.

[0011] Furthermore, a vent valve is arranged on the vent pipeline, and the vent valve is arranged in front of the flame arrester.

[0012] Furthermore, the nitrogen pipeline is a 0.46MPa nitrogen pipeline; the nitrogen pipeline is connected to the vent pipeline at the low point of the vent pipeline.

[0013] Furthermore, the waste oil tank is connected to the waste oil storage tank through a waste oil pump, and a pressure indicating instrument is arranged on the gas phase outlet pipeline, and the pressure indicating instrument controls the start and stop of the waste oil pump through a PLC.

[0014] Furthermore, the gas phase outlet pipeline is connected to the inlet of the waste oil storage tank through a branch pipeline.

[0015] The beneficial effects of the utility model are as follows: the fire prevention and vacuum prevention system of the waste oil tank of the utility model can control the upper space in the waste oil tank to be in a nitrogen protection state, and by adding a nitrogen pipeline, a self-operated regulating valve and a flow limiting orifice plate in the waste oil tank, the nitrogen protection state of the waste oil tank is always maintained. It is ensured that the gas mixture does not reach the ignition and explosion range when discharged to the flare and the atmosphere. At the same time, it is ensured that the pressure of the waste oil tank is automatically supplemented by the self-operated regulating valve when the waste oil is transported, so as to prevent the pump from failing to discharge after the tank reaches a negative pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a process flow chart of the fire prevention and vacuum prevention system for waste oil tanks of the utility model;

[0017] In the figure: 1. Sewage oil tank, 2. Nitrogen pipeline, 3. Gas phase outlet pipeline, 4. Vent pipeline, 5. Flare pipeline, 6. Flame arrester, 7. Self-operated regulating valve, 8. Drain valve, 9. Y-type filter, 10. Flow limiting orifice, 11. Fore-way valve, 12. Back-way valve, 13. Bypass line, 14. Bypass line valve, 15. 8-shaped blind plate, 16. Check valve, 17. Vent valve, 18. Sewage oil pump, 19. Pressure indicating instrument, 20. Branch pipeline, 21. Pressure gauge valve, 22. Pressure gauge.

[0018] A. Waste oil storage tank, B. Flare system. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0020] See attached Figure 1 A waste oil tank fire prevention and vacuum prevention system includes a waste oil tank 1 and a nitrogen pipeline 2. The tank top of the waste oil tank 1 is connected to a gas phase outlet pipeline 3, and the gas phase outlet pipeline 3 is respectively connected to a venting pipeline 4 and a flare pipeline 5. The venting pipeline 4 is provided with a flame arrester 6. The nitrogen pipeline 2 is connected to the venting pipeline 4, and a self-operated regulating valve 7 is provided on the nitrogen pipeline 2. The front of the self-operated regulating valve 7 is connected to a Y-type filter 9, and the back of the self-operated regulating valve 7 is connected to a flow limiting orifice.

[0021] Furthermore, the front and rear paths of the self-operated regulating valve 7 are respectively provided with a front valve 11 and a rear valve 12. The front valve 11, the self-operated regulating valve 7 and the rear valve 12 form a three-valve group, and the three-valve group is provided with a secondary line 13, and the secondary line 13 is connected to a secondary line valve 14. The rear path of the three-valve group is provided with an 8-shaped blind plate 15 and a one-way valve 16. A pressure gauge 22 and a pressure gauge valve 21 are provided after the self-operated regulating valve 7.

[0022] Furthermore, a vent valve 17 is provided on the vent pipeline 4 , and the vent valve 17 is provided before the flame arrester 6 .

[0023] Furthermore, the nitrogen pipeline 2 is a 0.46 MPa nitrogen pipeline; the nitrogen pipeline 2 is connected to the vent pipeline 4 at the low point of the vent pipeline.

[0024] Furthermore, the waste oil tank 1 is connected to the waste oil storage tank through a waste oil pump 18, and a pressure indicating instrument 19 is provided on the gas phase outlet pipeline 3, and the pressure indicating instrument 19 controls the start and stop of the waste oil pump 18 through a PLC.

[0025] Furthermore, the gas phase outlet pipeline 3 is connected to the inlet of the waste oil storage tank through a branch pipeline 20 .

[0026] The utility model has the following improvements: 1. A 0.46 MPa nitrogen pipeline 2 is added; 2. A nitrogen self-operated regulating valve 7 and front and rear valves 11, 12 and a flow limiting orifice 10 are added; 3. A flame arrester 6 is added to the atmospheric discharge line of the waste oil tank, and the height of the discharge port is increased. The discharge height must comply with the provisions of Article 5.5.11 of the GB50160 petrochemical enterprise design fire protection code, and must be 3.5 meters higher than the platform or building top within a range of 10 meters; 4. A low pressure alarm of the waste oil tank and PLC automatic control of stopping the waste oil pump are added.

[0027] The utility model of the waste oil tank fire prevention and vacuum prevention system can control the upper space in the waste oil tank to be in a nitrogen protection state. By adding a nitrogen pipeline, a self-operated regulating valve and a flow limiting orifice plate in the waste oil tank, the waste oil tank is always kept in a nitrogen protection state. It is ensured that the gas mixture does not reach the ignition and explosion range when discharged to the flare and the atmosphere. At the same time, it is ensured that the pressure of the waste oil tank is automatically supplemented by the self-operated regulating valve when the waste oil is transported, so as to prevent the pump from failing to discharge after the tank reaches a negative pressure.

[0028] The present invention does not disclose some common knowledge in the art.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A waste oil tank fire prevention and vacuum prevention system, characterized by: It includes a waste oil tank and a nitrogen pipeline. The tank top of the waste oil tank is connected to a gas phase outlet pipeline. The gas phase outlet pipeline is respectively connected to a vent pipeline and a flare pipeline. A flame arrester is arranged on the vent pipeline. The nitrogen pipeline is connected to the vent pipeline. A self-operated regulating valve is arranged on the nitrogen pipeline.

2. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: The front path of the self-operated regulating valve is connected to a Y-type filter, and the rear path of the self-operated regulating valve is connected to a flow limiting orifice plate.

3. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: The front and rear paths of the self-operated regulating valve are respectively provided with a front valve and a rear valve; a pressure gauge valve and a pressure gauge are provided behind the self-operated regulating valve.

4. A waste oil tank fire prevention and vacuum prevention system according to claim 3, characterized in that: The front-route valve, the self-operated regulating valve and the rear-route valve form a three-valve group, and the three-valve group is provided with a secondary line, and the secondary line is connected with a secondary line valve.

5. A waste oil tank fire prevention and vacuum prevention system according to claim 4, characterized in that: The rear path of the three-valve group is provided with an 8-shaped blind plate and a one-way valve.

6. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: A shower valve is provided at a low point of the nitrogen pipeline.

7. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: A vent valve is arranged on the vent pipeline, and the vent valve is arranged in front of the flame arrester.

8. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: The nitrogen pipeline is a 0.46MPa nitrogen pipeline; the nitrogen pipeline is connected to the vent pipeline at the low point of the vent pipeline.

9. A waste oil tank fire prevention and vacuum prevention system according to claim 1, characterized in that: The waste oil tank is connected to the waste oil storage tank through a waste oil pump, and a pressure indicating instrument is arranged on the gas phase outlet pipeline, and the pressure indicating instrument controls the start and stop of the waste oil pump through a PLC.

10. A waste oil tank fire prevention and vacuum prevention system according to claim 9, characterized in that: The gas phase outlet pipeline is connected to the inlet of the waste oil storage tank through a branch pipeline.

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