JPH0632799B2 - Method of cleaning oil and fat adhering to pipeline - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for cleaning oils and fats attached to pipelines, particularly flammable oils and fats.

[Prior art]

For example, a supply pipe that conveys oils and fats, especially fuels such as heavy oil or light oil at thermal power plants, factories, etc., or a pipeline that conveys combustible oils and fats such as naphtha at crude oil refining facilities,
Generally, the diameter is about 10 inches or more and the length reaches about 100 m or more. When such a long pipeline is removed, it is dismantled while being cut into appropriate lengths by gas fusing or a cutter saw or the like. However, there is a risk that sparks or the like generated at the time of gas fusing or cutting accompanying the above removal work may ignite the flammable oil or fat attached to the inside of the pipeline or the vaporized flammable gas. Generally, according to the Fire Service Act, the residual gas concentration in the pipeline is 14,000.
Must be below PPM. Therefore, in order to reduce the residual gas concentration by removing the combustible fats and oils and the combustible gas adhering to the inside prior to the cutting work, a cleaning method using a pig is adopted. That is, a pig is inserted into the pipeline according to the cleaning section, and a cleaning liquid is sprayed into the pipeline on the front side of the pig to clean the adhered oil and fat, and then the pipeline in the non-cleaning section is cleaned by the pig. The closed state is maintained to prevent the flammable gas from flowing out, and a part of the washed pipeline is cut.

[Problems to be Solved by the Invention]

However, since the pipeline is bent or folded back in a meandering manner in the crude oil refining heating pipe,
When cleaning the pipeline with the above-mentioned cleaning method, several meters
The pipeline could not be closed in units and the pig insertion and cleaning and cutting operations had to be repeated. As a result, in a long pipeline, the number of working steps increases, the working period becomes long, and the working efficiency is extremely poor. In addition, the above-mentioned cleaning method is a method of removing the oil and fat by emulsifying the oil and fat by filling the cleaning liquid in the section closed by the pig, and the oil and fat that has entered the recess on the inner surface of the pipeline cannot be washed and removed. The present invention was invented in order to solve the above-mentioned conventional drawbacks, and an object thereof is to efficiently burn combustible fats and oils and combustible gas adhering to the inside of a pipeline with a small number of working steps. Another object of the present invention is to provide a method of cleaning oils and fats adhering to a pipeline, which can be removed by cleaning and can prevent a fire from occurring.

[Means for solving problems]

Therefore, the present invention is a method of cleaning a long pipeline having a large diameter, which is arranged in a factory facility and conveys fats and oils, in which nitrogen that moves in a swirling motion is advanced with respect to one end of the pipeline whose both ends are open. Supplying a mixed fluid of gas and cleaning liquid to spread a large amount of oil and fat accumulated under the inside of the pipeline over the entire inner surface, causing the cleaning liquid to act and emulsify,
It is characterized in that the entire area from the start end to the end is washed and removed.

[Operation of the invention]

Since it is configured like the tree of the present invention, when a swirling mixture of nitrogen gas and the cleaning liquid is supplied into the pipeline, this mixed flow causes oil and fat accumulated below the pipeline to flow into the pipeline. It is removed by emulsifying by applying a cleaning liquid while spreading it over the entire peripheral surface.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing the outline of the cleaning method. A pipeline 1 for conveying flammable fats and oils in a thermal power plant or a crude oil refining facility has a diameter of 10 inches or more and a length of several hundred meters.
Above (the heating pipe for crude oil refining reaches several kilometers above), it is appropriately bent according to the plant layout, or folded back in a meandering shape in the heating furnace. Prior to the cleaning operation, both ends of the pipeline 1 are cut open. A substantially cylindrical jet head 3 is attached to one open end of the pipeline 1, and a cleaning liquid supply nozzle 7 extending from the opposite end of the pipeline 1 is provided in the jet head 3. There is. A baffle plate 9 having a size corresponding to the inner diameter of the jet head 3 is provided at a part of the cleaning liquid supply nozzle 7. The baffle plate 9 is substantially disk-shaped and has a plurality of slits 9a extending in the radial direction from the center.
And a part of the baffle plate 9 corresponding to the slit 9a is bent and formed so as to face the axial direction and the radial direction. Further, a supply pipe 5 for supplying nitrogen gas as a non-combustible gas is provided between the jet head 3 and the baffle plate 9 in the jet head 3, and the nitrogen gas supplied from the supply pipe 5 is A swirling gas flow that swirls around the axis while advancing in the axial direction as the baffle plate 9 passes through the slit 9a is formed. Nitrogen gas is suitable as the non-combustible gas in terms of cost and prevention of air pollution, but is not limited thereto. A control manifold, an evaporator and a liquid nitrogen tank (none of which are shown) are connected to the supply pipe 5, so that a predetermined flow rate of nitrogen gas is supplied to the one end side of the pipeline 1 through the injection head 3. It has become. Further, a cleaning liquid supply nozzle 11 is attached to an end portion of the jet head 3, and a supply pipe 13 from a cleaning liquid tank (not shown) 9 is connected to the cleaning liquid supply nozzle 11 and is connected to the jet head 3. A predetermined amount of cleaning liquid is supplied. As this cleaning liquid, for example, "Snow Wrap" (manufactured by Nissan Chemical Industries, Ltd.) containing an alkyl-based special nonionic surfactant as a main component is suitable, but the cleaning liquid used in the present invention is a surfactant having an action of emulsifying fats and oils. Any agent may be used, and the agent is not limited to this. The cleaning liquid is adjusted to about 20 to 100% by volume with water according to the type of oil or fat to be cleaned and removed. When the nitrogen gas is swirlingly formed in the jet head 3, the cleaning liquid is supplied to the swirling gas flow with respect to the swirling gas flow.
7 and mixed. When nitrogen gas having a required flow velocity and flow rate is supplied to the jet head 3 configured as described above in the direction of a solid arrow A shown in FIG. 1, the jet head 3 is used to enter the pipeline 1. When cleaning the adhered combustible oil and fat, the combustible oil and fat accumulated below the pipeline 1 is adhered to almost the entire inner surface of the pipeline 1 by the nitrogen gas that swirls in the pipeline 1 and the nitrogen After being emulsified by the cleaning liquid that works together with the gas, it is exfoliated from the inner peripheral surface of the pipeline 1 by the pressure of nitrogen gas and extruded toward the other end of the pipeline 1 along the inner surface thereof. At this time, since the nitrogen gas and the cleaning liquid are swirling, the above operation is achieved from the starting end of the pipeline 1. Therefore, as compared with the case where the mixed flow of the nitrogen gas and the cleaning liquid is supplied straight to the pipeline 1, the combustible oil and fat accumulated in the lower portion of the pipeline 1 is pushed to the upper side of the pipeline 1 so as to be applied. It is possible to unfold and spread it almost evenly on the inside for cleaning, and it is possible to shorten the cleaning time. By swirling the mixed flow of the nitrogen gas and the cleaning liquid in this way, the combustible oil and fat can be emulsified and cleaned while being spread over the entire inside of the pipeline 1, and the cleaning time can be greatly shortened. It is possible. The emulsified oil and fat and vaporized gas discharged from the opening at the other end of the pipeline 1 are collected by a collection device (not shown) to prevent external contamination. Further, in the above description, the cleaning liquid is sucked into the ejection head 3 by the negative pressure accompanying the passage of the nitrogen gas into the ejection head 3. However, a part of the nitrogen gas is used to pressurize the cleaning liquid. A mode in which a predetermined amount of cleaning liquid is supplied into the ejection head 3 may be used. Further, in the embodiment shown in the drawings, the nitrogen gas supply arrangement 5 is connected to the pipeline 1 side of the jet head 3 and the cleaning liquid supply pipe 13 is provided at the end thereof, but nitrogen gas is provided at the end. The cleaning liquid supply pipe 13 may be provided in the middle portion of the injection head 3, and the cleaning liquid may be sucked into the injection head 3 by the negative pressure generated by the flow of the nitrogen gas in the injection head 3. Example Pipeline diameter and length 16 inch ……… 1.180 m Types of fats and oils Fuel oil (naphtha) Nitrogen gas flow rate 30 to 70 m / sec Cleaning solution “Snow Wrap” (manufactured by Nissan Kagaku) and water mixing ratio 50 volumes % Number of times of cleaning 5 times Residual gas concentration after cleaning 100-200PPM Residual gas concentration when cleaning with water after cleaning 0PPM The above explanation describes the combustible oil and fat adhering to the pipeline 1 due to the cleaning with the cleaning liquid and the combustible gas generated from this. Although it is supposed to be removed, the inside of the pipeline may be washed with water after the above-mentioned work and the oil and fat adhering to the inside of the washed pipeline with an abrasive may be removed.

【The invention's effect】

As described above, the present invention can efficiently remove the flammable oil and flammable gas and the flammable gas adhering to the inside of the pipeline with a small number of work strokes, and can prevent the occurrence of fire from the oil and fat adhering to the pipeline. It is possible to provide a cleaning method.

[Brief description of drawings]

 FIG. 1 is an explanatory view showing the outline of the cleaning method. In the figure, 1 is a pipeline.

Front page continuation (72) Inventor Yukio Sasaki 4-73, Miyoshi-cho, Minami-ku, Nagoya, Aichi Japan Facility Conservation Co., Ltd. (56) Reference JP-A-59-225788 (JP, A) JP-A-48 -102159 (JP, A) JP-A-57-117379 (JP, A) JP-A-57-146200 (JP, A) JP-A-60-256100 (JP, A) JP-A-62-117689 (JP-A) ) Actual public Sho 60-31835 (JP, Y2)

Claims (1)

[Claims] 1. A method for cleaning a long pipeline having a large diameter, which is arranged in a factory facility and conveys fats and oils,
To the one end of the pipeline whose both ends are open, supply the mixed fluid of the cleaning liquid added to the nitrogen gas that moves in a swirling motion to spread the large amount of oil and fat accumulated under the inside of the pipeline over the entire inner surface to provide the cleaning liquid. A method for cleaning oil and fat adhering to a pipeline, which comprises emulsifying and emulsifying and washing and removing the whole from the start end to the end.