Internal oxygen content monitoring system for oil and gas storage and transportation pipeline

Abstract

The utility model provides an internal oxygen content monitoring system for an oil gas storage and transportation pipeline, which comprises a conveying pipeline and a nitrogen branch which are arranged between a source end and an oil gas treatment system, an oxygen analyzer is connected onto the conveying pipeline, a stop valve is mounted on the conveying pipeline, a nitrogen regulating valve is arranged on the nitrogen branch, and the nitrogen regulating valve is connected with the oxygen analyzer. And a nitrogen source is arranged at the source of the nitrogen branch. An inlet of the oil gas treatment system is modified, the oxygen content analyzer is additionally arranged, meanwhile, high-purity nitrogen is introduced into the front end of the oxygen content analyzer, when the system detects that the oxygen content in an oil gas pipeline is too high, the nitrogen adjusting valve is automatically opened, nitrogen is supplemented into the pipeline, and when the oxygen content in the oil gas pipeline is reduced, the nitrogen adjusting valve is automatically closed. In the prior art, an oil gas storage and transportation treatment system is not provided with an oxygen content monitoring and nitrogen supplementing system in the earlier stage, after the device is applied, the oxygen content in an oil gas pipeline can be effectively controlled, safety accidents are prevented, the device is officially put into use at present, and the prevention effect is good.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of petroleum chemical industry especially relates to the inside oxygen content monitoring system of oil gas pipeline of storage and transportation. BACKGROUND

[0002] As the important link of connecting upstream and downstream industries and adjusting various production devices, the storage and transportation system has an important position in the production, transfer, sales, import and export links, and the VOCs of the storage and transportation system accounts for a large proportion in various emission sources. With the increasing emphasis of the country on environmental protection, the requirements of the storage and transportation system on oil gas emission are also more and more strict, and while achieving environmental protection, the safety of the oil gas treatment system should also be ensured.

[0003] The VOCs of the storage and transportation system mainly come from the large and small breathing of the atmospheric storage tank, the oil gas generated by the automobile loading and unloading, ship and the like. At present, the main ways of the storage and transportation system for treating oil gas are burning and oil gas recovery. However, before the oil gas enters the oil gas treatment system, air often enters the oil gas pipeline when the large and small breathing of the atmospheric storage tank, the automobile loading and unloading and the loading and unloading of the cargo ship, and the oil gas and the air are mixed to easily form an explosive mixture. If the flow rate is too fast to generate static electricity or sparks are generated due to equipment failure during the operation of the oil gas treatment device, flash explosion may occur, which may cause serious consequences.

[0004] Therefore, in order to prevent such accidents, it is the key to solve the problem to control the oxygen content in the oil gas pipeline at the source. UTILITY MODEL CONTENT

[0005] According to the above technical problem, an inside oxygen content monitoring system of oil gas pipeline of storage and transportation is provided. The technical means adopted by the utility model is as follows:

[0006] An inside oxygen content monitoring system of oil gas pipeline of storage and transportation, comprising a conveying pipeline and a nitrogen branch pipeline arranged between a source end and an oil gas treatment system, an oxygen analyzer connected to the conveying pipeline, a cut-off valve installed on the conveying pipeline, and a nitrogen regulating valve arranged on the nitrogen branch pipeline.

[0007] Further, the cut-off valve is an electric valve.

[0008] Further, the nitrogen regulating valve is an electric valve.

[0009] Further, the oxygen analyzer, the cut-off valve and the nitrogen regulating valve are electrically connected with a DCS system.

[0010] Further, the source end comprises a storage tank, an automobile loading and unloading or a ship.

[0011] This utility model has the following advantages: It modifies the inlet of the oil and gas processing system, adds an oxygen content analyzer, and introduces high-purity nitrogen gas at the front end of the oxygen content analyzer. When the system detects that the oxygen content in the oil and gas pipeline is too high, the nitrogen control valve automatically opens to replenish nitrogen into the pipeline. When the oxygen content in the oil and gas pipeline decreases, the nitrogen control valve automatically closes. Existing oil and gas storage and transportation processing systems do not have oxygen content monitoring and nitrogen replenishment systems in their early stages. With the application of this utility model, the oxygen content in the oil and gas pipeline can be effectively controlled, preventing the occurrence of safety accidents. It has now been officially put into use and has achieved good preventive effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0013] Figure 1 This is a schematic diagram of the utility model system.

[0014] Figure 2 This is a schematic diagram of oxygen content control in the specific implementation of the present utility model. DETAILED DESCRIPTION

[0015] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] To prevent the excessive oxygen content in the pipelines of the oil and gas processing facilities of the storage and transportation system from causing flash explosions and safety accidents, such as Figure 1 、 2 As shown, an embodiment of the utility model discloses a system for monitoring the internal oxygen content of an oil and gas storage and transportation pipeline, comprising a delivery pipeline and a nitrogen branch arranged between a source end and an oil and gas processing system, an oxygen analyzer being connected to the delivery pipeline, a shut-off valve being installed on the delivery pipeline, and a nitrogen regulating valve being provided on the nitrogen branch.

[0017] In this embodiment, the shut-off valve is an electric valve. The nitrogen regulating valve is an electric valve.

[0018] The oxygen analyzer, cut-off valve and nitrogen regulating valve are electrically connected with the DCS system. In this embodiment, an oxygen analyzer is arranged to monitor the oxygen content in the pipeline before the exhaust gas enters the oil and gas treatment system. The DCS input sets a value, and when the oxygen content in the pipeline is higher than the set value, the nitrogen regulating valve is automatically opened, and when the oxygen content is higher than the set value, the nitrogen regulating valve is automatically closed, so as to balance the oxygen content in the pipeline. In this process, the opening and closing of the cut-off valve is also controlled, so that the oxygen content is accurately controlled before being discharged into the oil and gas treatment system.

[0019] In this embodiment, the source end includes a storage tank, a vehicle loading and unloading vehicle or a ship.

[0020] Specifically, an oxygen content monitoring system is designed and implemented for the oil and gas treatment system. Based on the oxygen content monitoring data, a safety control strategy is developed to prevent the oil and gas mixture from reaching a flammable concentration during the treatment process. This includes setting a safety threshold for oxygen content and automatically implementing control measures such as starting the inerting system or closing the electric cut-off valve when excessive is detected. The following effects can be achieved;

[0021] 1. Improve production safety: By monitoring the oxygen content in the oil and gas treatment system in real time, combustion or explosion accidents caused by improper oxygen concentration can be prevented.

[0022] 2. Prevent combustion and explosion risk: In oil and gas recovery operations, the oxygen analyzer sensor can trigger the inerting system to reduce the oxygen content and prevent accidents.

[0023] In this embodiment, the pipeline length is 150m 3 Taking oil and gas recovery as an example;

[0024] The oxygen content increases linearly during the loading process. The nitrogen injection system is opened to inject nitrogen into the pipeline to effectively control the oxygen content below 8%, avoiding the possibility of forming explosives due to high oxygen content and oil and gas mixture during oil and gas recovery operation, greatly improving the safety and stability of oil and gas recovery operation;

[0025] The oil and gas in the storage and transportation system enters the oil and gas treatment system through the pipeline. When passing through the oxygen analyzer, (for example, according to JTT1333-2020, the industry standard for port oil and gas recovery ship shore safety devices 5.16.3; when the design volume ratio of oxygen analysis oxygen content reaches 8%, over-limit control should be implemented). Therefore, when the oxygen analyzer detects that the oxygen content in the pipeline gradually increases to 3% or 5% (the value can be adjusted according to the actual situation on site), the nitrogen regulating valve is opened to inject nitrogen into the pipeline to reduce the oxygen content. The nitrogen regulating valve adjusts the valve opening according to the oxygen content, and at the same time, the oil and gas recovery is normally operated.

[0026] During the oil and gas recovery operation, the oxygen content may still exceed the standard when nitrogen is added. During this period, the oil and gas recovery operation is stopped, the shut-off valve is closed, the nitrogen regulating valve is opened, and nitrogen is continuously added until the oxygen content drops to within the normal value.

[0027] When the oil and gas recovery stops running due to excessively high oxygen content, the shut-off valve opens after the oxygen content of the oil and gas decreases by adding nitrogen, and the oil and gas processing system automatically runs and returns to normal.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for monitoring oxygen content inside oil and gas storage and transportation pipelines, characterized in that: It includes a delivery pipeline and a nitrogen branch line arranged between the source end and the oil and gas processing system. The delivery pipeline is connected to an oxygen analyzer, a shut-off valve is installed on the delivery pipeline, and a nitrogen regulating valve is installed on the nitrogen branch line. The source end includes a storage tank, a truck or a ship. The oxygen analyzer, shut-off valve, and nitrogen regulating valve are all electrically connected to the DCS system. The DCS system is used to input set values. When the oxygen content in the pipeline is higher than the set value, the nitrogen regulating valve automatically opens. When the oxygen content is higher than the set value, the nitrogen regulating valve automatically closes. The oxygen analyzer detects the oxygen content in the pipeline at a threshold of 3% or 5%.

2. The internal oxygen content monitoring system of the oil and gas storage and transportation pipeline according to claim 1 is characterized in that: The shut-off valve is an electric valve.

3. The internal oxygen content monitoring system of the oil and gas storage and transportation pipeline according to claim 1 is characterized in that: The nitrogen regulating valve is an electric valve.

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