Pipeline cleaning system and cleaning methods for wharf asphalt transportation pipelines

Abstract

This invention relates to a cleaning system and method for asphalt conveying pipelines at wharves. The wharf asphalt conveying pipeline cleaning system includes an asphalt low-level tank and a secondary conveying pipeline. The asphalt low-level tank is connected to the front end of the main unloading pipeline via a discharge pipe, and a submersible pump is installed inside the asphalt low-level tank. The end of the secondary conveying pipeline is connected to an asphalt storage tank, and the front end of the secondary conveying pipeline is connected to the submersible pump. Both the main unloading pipeline and the secondary conveying pipeline have a slope of 2-5‰, decreasing in height towards the asphalt low-level tank. A heating coil is installed inside the asphalt low-level tank. This invention fully utilizes the elevation difference between the pipeline and the asphalt low-level tank, using gravity flow to recover the asphalt in the pipeline. This ensures that the pipeline remains free of media during non-unloading periods, eliminating the need for a continuous supply of heating steam or other media to maintain the system temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of asphalt transportation, and specifically relates to a pigging system for a terminal asphalt transportation pipeline and a pigging method using the pigging operation. Background Art

[0002] Asphalt is a highly viscous and easily solidifiable organic liquid, which is a dark brown complex mixture composed of hydrocarbon compounds with different molecular weights and their non-metallic derivatives. It is a kind of highly viscous organic liquid and mostly exists in the form of liquid or semi-solid petroleum. The freezing point of the asphalt involved in the present invention is about 120°C.

[0003] When unloading asphalt from a ship, a metal hose is used to connect the asphalt cargo ship and the long-distance transportation pipeline (main unloading pipeline), and the asphalt is transported to an asphalt storage tank. The asphalt unloading work is usually only carried out one to two times within a month, but the heat tracing system配套 with the long-distance transportation pipeline for asphalt unloading must be kept open 24 hours a day throughout the year to ensure that the asphalt in the pipeline system is in a flowing state, resulting in very high operating energy consumption. After the unloading work is completed, the residual asphalt in the metal hose needs to be manually drained into a temporary oil barrel and then transferred to the asphalt storage tank for a second time.

[0004] The problems existing in the prior art mainly include:

[0005] The heat tracing system of the long-distance transportation pipeline for asphalt unloading does not allow shutdown and is in a long-term heating state, resulting in very high heat energy consumption during operation, which increases the operating cost of the factory.

[0006] Long-term heating will cause the asphalt to deteriorate and affect the quality of the product.

[0007] Long-term high temperature may cause the asphalt to coke in the pipeline, increasing the maintenance cost.

[0008] After the unloading work is completed, the residual asphalt in the metal hose needs to be manually drained into a temporary oil barrel. The exposed operation of high-temperature asphalt may pose a risk of scalding accidents.

[0009] After the unloading work is completed, the asphalt drained into the oil barrel needs to be transferred to the asphalt storage tank for a second time, increasing the workload of the operators. Improper operation may pose a risk of leakage, causing environmental pollution. Summary of the Invention

[0010] r The technical problem to be solved by the present invention is to provide a pigging system and a pigging method for a terminal asphalt transportation pipeline, so that the pipeline can be kept without medium during non-unloading periods, and there is no need to continuously supply medium such as tracing steam for a long time to maintain the temperature of the system. j

[0011] To solve the above technical problems, according to one aspect of the present invention, a wharf asphalt conveying pipeline cleaning system is provided, comprising an asphalt low-level tank and a secondary conveying pipeline;

[0012] The asphalt low-level tank is connected to the front end of the main unloading pipeline via a discharge pipe, and a submersible pump is installed inside the asphalt low-level tank; the end of the secondary conveying pipeline is connected to the asphalt storage tank, and the front end of the secondary conveying pipeline is connected to the submersible pump.

[0013] Both the main unloading pipeline and the secondary conveying pipeline have a slope that decreases in height towards the asphalt low-level tank.

[0014] Furthermore, the main unloading pipeline has a slope of 2-5‰, which decreases in height towards the asphalt low-level tank.

[0015] Furthermore, the secondary conveying pipeline has a slope of 2-5‰, which decreases in height towards the asphalt low-level tank.

[0016] Furthermore, a heating inner coil is installed inside the asphalt low-level tank.

[0017] Furthermore, both the main unloading pipeline and the secondary conveying pipeline are equipped with heat tracing pipes on their outer sides.

[0018] Furthermore, a heating device is installed inside the asphalt storage tank.

[0019] According to another aspect of the present invention, a method for cleaning a wharf asphalt conveying pipeline is provided. This method employs the aforementioned wharf asphalt conveying pipeline cleaning system. After the asphalt unloading operation is completed, the shut-off valve of the metal hose connecting the asphalt cargo ship and the main unloading pipeline is closed, and the discharge valve on the discharge pipe is opened. Utilizing the slope of the main unloading pipeline, the asphalt inside the main unloading pipeline flows back into the asphalt low-level tank, thereby completely emptying and recovering the asphalt in the main unloading pipeline. After the asphalt in the main unloading pipeline is drained, a submersible pump is started to transport the asphalt in the asphalt low-level tank to the asphalt storage tank through a secondary conveying pipeline. After the asphalt is emptied, the pump is stopped, and the slope of the secondary conveying pipeline is used again to allow the asphalt in the pipeline to flow back into the asphalt low-level tank.

[0020] Furthermore, the interior of the asphalt low-level tank is heated by coils to keep the asphalt storage temperature above the freezing point.

[0021] This invention provides a low-energy-consumption wharf asphalt cleaning system and method. It employs a simple and reasonable device, fully utilizing the elevation difference between the pipeline and the asphalt low-level tank, and uses gravity flow to recover the asphalt from the pipeline. This ensures that the pipeline remains free of media during non-unloading periods, eliminating the need for a continuous supply of heating steam or other media to maintain the system temperature. This solves the high-energy-consumption problem of existing asphalt systems requiring constant heating of the pipeline, reduces carbon emission intensity, and achieves the goal of saving operating costs.

[0022] In addition to being applicable to the transportation of asphalt, this invention is also applicable to the transportation of other easily solidified chemical fluid media. Attached Figure Description

[0023] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0024] Figure 1 This is a schematic diagram of the structure of a wharf asphalt conveying system in the existing technology.

[0025] Figure 2 This is a schematic diagram of the overall structure of the wharf asphalt conveying system described in this invention.

[0026] In the diagram, 1-Asphalt low-level tank, 2-Secondary conveying pipeline, 3-Discharge pipe, 4-Unloading main pipeline, 5-Submersible pump, 6-Asphalt storage tank, 7-Metal hose, 8-Asphalt cargo ship, 9-Discharge valve, 10-Heating inner coil, 11-Heating pipeline. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the present invention will be further described clearly and completely below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0028] A typical embodiment of the present invention provides a wharf asphalt conveying pipeline cleaning system comprising an asphalt low-level tank 1 and a secondary conveying pipeline 2. The asphalt low-level tank 2 is connected to the front end of the main unloading pipeline 4 via a discharge pipe 3. A submersible pump 5 is installed inside the asphalt low-level tank 1, and a discharge valve 9 is installed on the discharge pipe 3. The end of the secondary conveying pipeline 2 is connected to an asphalt storage tank 6, and the front end of the secondary conveying pipeline 2 is connected to the submersible pump 5. A metal flexible hose 7 connects the asphalt cargo ship 8 to the front end of the main unloading pipeline 4.

[0029] Both the main unloading pipeline 4 and the secondary conveying pipeline 2 have a slope that decreases in height towards the asphalt low-level tank 1.

[0030] The basic concept of this invention is to utilize the height difference between the main unloading pipeline 4, the secondary conveying pipeline 2 and the asphalt low-level tank 1 to recover the asphalt in the pipeline by gravity flow, so that there is no medium in the pipeline during non-unloading periods, and there is no need to continuously supply heating steam or other media to maintain the temperature of the system.

[0031] In the above embodiments, the asphalt low-level tank 1 is used to store the drained asphalt, and its volume should be 20% larger than the total volume of the unloading pipeline. The asphalt low-level tank 1 can serve as an intermediate bridge for asphalt transportation in the pigging system, playing a transitional role.

[0032] The asphalt remaining in the main asphalt unloading pipeline 4 is discharged into the asphalt low-level tank 1 using discharge pipe 3 and discharge valve 9. The discharge valve 9 is installed near the dock and at the lowest point in the entire system layout to ensure the thoroughness of the discharge work.

[0033] A submersible pump 5 is used to transport asphalt from the asphalt low-level tank 1 to the asphalt storage tank 6. The submersible pump 5 can pump liquid from equipment at lower elevations and ensure that there is no residue in the pipeline after the liquid flows back.

[0034] A large amount of asphalt in the asphalt low-level tank 1 is transported to the asphalt storage tank 6 using the asphalt secondary transportation pipeline 2.

[0035] In a preferred embodiment, the main unloading pipeline 4 has a slope of 2-5‰ that decreases in height towards the asphalt low-level tank 1, and the secondary conveying pipeline 2 has a slope of 2-5‰ that decreases in height towards the asphalt low-level tank 1, so as to facilitate the recovery of asphalt in the pipelines.

[0036] In a preferred embodiment, a heating inner coil 10 is provided in the lower middle part of the asphalt low-level tank 1 to maintain the temperature of the asphalt during the discharge process. The asphalt unloading main pipeline 4 and the secondary conveying pipeline 2 need to be equipped with heat tracing pipelines 11 to prevent the asphalt from solidifying due to low temperature during the unloading and conveying process.

[0037] According to the above-described wharf asphalt conveying pipeline cleaning system, the pipeline cleaning method is as follows: After the asphalt unloading work is completed, close the shut-off valve of the metal hose 7 connecting the asphalt cargo ship 8 and the main unloading pipeline 4, open the discharge valve 9 on the discharge pipe 3, and use the slope of the main unloading pipeline 4 to allow the asphalt inside the main unloading pipeline 4 to flow back into the asphalt low-level tank 1, thereby emptying and recycling all the asphalt in the main unloading pipeline 4; after the asphalt in the main unloading pipeline 4 is drained, start the submersible pump 5 to transport the asphalt in the asphalt low-level tank 1 to the asphalt storage tank 6 through the secondary conveying pipeline 2. After the asphalt is emptied, stop the pump, and then use the slope of the secondary conveying pipeline 2 to allow the asphalt in the pipeline to flow back into the asphalt low-level tank 1.

[0038] With this invention, the temperature of the asphalt pipe only needs to be maintained by opening the heat tracing pipe 11 during the unloading process. When the ship is not unloading, the pipe remains empty. A large number of heat tracing pipes 11 do not need to be operated and do not consume heat energy. In this way, energy is saved, the operating cost of the plant is reduced, and carbon emissions are reduced.

[0039] After the asphalt unloading operation is completed, close the shut-off valve on the metal hose 7 and open the discharge valve 9 at the lowest point of the dock pipeline. Utilizing the 2-5‰ slope of the main asphalt unloading pipeline 4, the asphalt inside the main pipeline 4 flows back into the asphalt low-level tank 1, thus completely emptying and recycling the asphalt in the main pipeline 4. The volume of the asphalt low-level tank 1 must be calculated and determined, and this storage volume must be greater than or equal to 1.2 times the volume of the main pipeline 4. The asphalt low-level tank 1 is designed with coil heating to ensure that the asphalt storage temperature is above the freezing point. After the asphalt in the main pipeline 4 is completely drained, start the submersible pump 5 to discharge the asphalt into the low-level tank. The asphalt in tank 1 is transported to asphalt storage tank 6 via secondary conveying pipe 2. After the asphalt pump is emptied, the pump is stopped. The secondary conveying pipe, with its 2-5‰ slope, allows the asphalt in it to flow back into the asphalt low-level tank 1. The diameter of the secondary conveying pipe 2 is one-sixth that of the main unloading pipe 4. Therefore, the amount of asphalt flowing back is only about one-thirty-sixth (2.78%) of the amount stored in the main unloading pipe. This portion of asphalt is temporarily stored at the bottom of the asphalt low-level tank 1 and will be mixed with the asphalt for the next unloading operation before further processing. At this point, 97.2% of the asphalt in the main unloading pipe 4 has entered the asphalt storage tank 6. A small amount of asphalt remaining at the metal hose 7 can also flow back into the asphalt low-level tank 1. After the operation is completed, the heating system of the asphalt pipeline is shut off, awaiting the next unloading operation.

[0040] The pipeline cleaning system described above is simple in equipment, consumes little heat energy, and has low operating costs, achieving low-carbon operation. It rationally utilizes the elevation difference in equipment and pipeline layout without consuming additional power. Using the above-described cleaning method, the asphalt does not need to undergo prolonged high-temperature treatment, maximizing product quality; it also avoids the problem of asphalt coking inside the pipeline, resulting in lower maintenance costs.

[0041] After unloading is completed, any residual asphalt inside the metal hose can be automatically discharged into a low-level tank for centralized treatment, eliminating the need for manual transfer to oil drums and reducing the workload of operators. The entire system operates in a closed loop, eliminating the risk of leaks and environmental pollution.

[0042] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method of pigging a wharf bitumen transfer pipeline, characterised by: The invention discloses a wharf asphalt conveying pipeline pigging system. The wharf asphalt conveying pipeline pigging system comprises an asphalt low-position tank and a secondary conveying pipeline. The asphalt low-position tank is connected with the front end of the unloading main pipeline through a discharge pipe, and a submersible pump is arranged in the asphalt low-position tank. The secondary conveying pipeline is connected with the asphalt storage tank at the end, and connected with the submersible pump at the front end. Both the unloading main pipeline and the secondary conveying pipeline have a slope decreasing in height towards the asphalt low-position tank. The unloading main pipeline has a slope decreasing in height towards the asphalt low-position tank at 2-5‰. The secondary conveying pipeline has a slope decreasing in height towards the asphalt low-position tank at 2-5‰. A heating inner coil is arranged in the asphalt low-position tank.

2. The method of claim 1, wherein: After the asphalt unloading work is completed, the cut-off valve of the metal hose connecting the asphalt cargo ship and the unloading main pipeline is closed, the discharge valve on the discharge pipe is opened, and the asphalt in the unloading main pipeline is caused to flow back to the asphalt low-position tank by the slope of the unloading main pipeline, so that the asphalt in the unloading main pipeline is completely emptied and recovered.

3. The method according to claim 1 or 2, characterized in that: After the asphalt in the unloading main pipeline is completely discharged, the submersible pump is started to convey the asphalt in the asphalt low-position tank to the asphalt storage tank through the secondary conveying pipeline, the pump is stopped after the asphalt is emptied, and the asphalt in the secondary conveying pipeline is caused to flow back to the asphalt low-position tank by the slope of the secondary conveying pipeline.

4. The method of claim 3, wherein: The inner coil is used to heat the asphalt low-position tank to keep the temperature of the stored asphalt above the freezing point. Both the unloading main pipeline and the secondary conveying pipeline are provided with a heating pipeline outside. A heating device is arranged in the asphalt storage tank.

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