JPH0322202B2 - - Google Patents

Description

[Detailed description of the invention]

purpose of invention

[Industrial application field]

The present invention relates to a strainer attached to a transfer device for crude oil, etc., and is particularly directed to a strainer installed on the suction side of a pump at a crude oil storage base to remove solid foreign matter that may damage the pump.

[Conventional technology]

Due to the nature of crude oil storage facilities, the crude oil is not heated in the tanks or piping, at least while it is being stockpiled. The following problems occur during the winter when attempting to remove crude oil stored in tanks for purposes such as depleting stockpiles or refilling tanks. In other words, in winter, the oil temperature is low, especially in cold regions, reaching several tens of degrees below zero, so the water in the crude oil freezes and forms "ice sludge."
The problem is that the suction strainer of the pump is blocked, causing cavitation in the pump. The phenomenon in which ice sludge formed in crude oil clogs the strainer is thought to be related to the type of crude oil and moisture content in addition to external conditions such as temperature, and there are various forms, but the inventors' In my experience, the following two cases are common. One type is a "smiling" formation of crude oil and water around small pieces of ice, which can range in size from the size of a fist to the size of a person's head. There are needle-shaped ice crystals scattered within this smiley substance. Another problem is that the water freezes into grainy ice pieces several millimeters in size, which fill the mesh of the strainer. Although these solid substances adhering to the strainer are not necessarily sufficient to destroy the pump by themselves, a strainer must be used in case other foreign substances are present. A similar problem exists with "waxy sludge," which occurs in crude oil that does not contain water but has a high wax content. Conventionally, there has been no effective countermeasure against strainer blockage for either problem.

[Problems to be solved by the invention]

In preparation for the above-mentioned situation, the purpose of the present invention is to remove foreign substances originally contained in crude oil and to remove ice sludge and/or waxy sludge (hereinafter referred to as
The object of the present invention is to provide an apparatus that processes sludge (collectively referred to as "sludge") by melting it and passing it through a strainer without taking it out of the system. Composition of the invention

[Means to solve the problem]

The strainer of the present invention is a strainer used in a flow path for a liquid containing solids that precipitate as the temperature falls and melts and disappears as the temperature rises, and is provided with an inlet 11 and an outlet 12 for the liquid as shown in the drawing. It consists of a vertical cylindrical filtration chamber 1 and a heating chamber 2 below the filtration chamber 1, and the filtration chamber 1 has a cylindrical filtration element 3 vertically fixed therein and allows liquid to pass from the inside to the outside. A rotating shaft 41 passing through the center of the filtration element 3 is provided with scraping means 4 for scraping and dropping the solid matter adhering to the inside of the element, and a means for rotationally driving this shaft (not shown) is provided. ), and is characterized by having a heating means 5 for melting the solid matter scraped inside the heating chamber 2.

[Effect]

When the crude oil containing sludge enters the filtration chamber through the above-mentioned strainer in the direction of the arrow from the liquid inlet 11 and passes through the filtration element 3, the sludge along with other solids (if any) adheres to the inside of the filtration element; It is continuously scraped off by the scraping means 4 and falls into the heating chamber. Therefore, the heating means 5
The oil is heated together with the surrounding crude oil and melts back to liquid form. The crude oil containing the sludge melt rises in the heating chamber as the temperature increases, returns to the filtration chamber 1, passes through the filtration element and exits through the liquid outlet 12 together with the crude oil from the inlet 11. Unmelted solids sink to the bottom of the heating chamber and are discharged from drain 21 once they have accumulated.

[Embodiment]

The filtration element constituting the strainer may be made of woven metal wire or punched metal. The means for scraping off deposits preferably has a twisted shape so that the debris scraped off as it rotates is reliably pushed downward and falls. Further, it is preferable to maintain close contact with the filter element by an appropriate method such as using a spring. Regarding these points, techniques already known in the field of strainers may be followed. The heating means 5 is most typically a coil for passing steam as shown in the figure, but may be any other means such as using combustion gas or electric heating. In order to pass the sludge component melted in the heating chamber through the filtration element together with the surrounding crude oil, it is necessary to return it to the filtration chamber in an upward flow. As mentioned above, this objective can be achieved by increasing the temperature and creating a difference in specific gravity, but it is preferable to take active measures to ensure upward flow. In the illustrated example, this is done by attaching a blade 6 to the center of the heating chamber. This blade may be a screw. The blades or screws may be rotated by the same rotating shaft 41 as the scraping means, but if a separate rotating shaft is provided, the structure will be complicated, but it will be convenient for operation. More preferably, as also shown in the figure, a cylinder 7 having a smaller diameter than the filtration element and having a liquid flow passage 71 at the lower part is provided around the blade,
Separate falling sludge from upward flow. This cylinder may be provided with a number of small holes on the side, instead of or in addition to the fluid flow passage 71 at the bottom. If the upward flow around the heating chamber is promoted, the downward flow around the heating chamber will also be promoted, and contact of the sludge with the heating means will be promoted. In addition to the above, there may be many variations to the strainer of the present invention. Effects of the Invention The strainer of the present invention removes original foreign substances from the liquid, including the above-mentioned crude oil and sludge that precipitates as the temperature drops and melts and disappears as the temperature rises, and allows everything else to pass through as a liquid. There are no problems with sludge treatment, and it can be used in the same way as a conventional strainer. The thermal energy required by the heating means is only required to heat a small portion of the liquid passing through it to the sludge melting temperature, compared to installing a heater inside the tank or piping to raise the overall oil temperature. It is easy to see that much less would be required. Of course, this strainer only needs to be operated when the pump is driven.

[Brief explanation of drawings]

The drawings show an example of the strainer of the present invention, in which FIG. 1 is a longitudinal cross-sectional view, FIG. 2 is a cross-sectional view from the position shown in FIG. 1, and FIG.
FIG. 3 is a cross-sectional view of the position. 1...Filtering chamber, 2...Heating chamber, 3...Filtering element, 4...Scraping means, 5...Heating means,
6...Blade, 7...Small diameter cylinder.

Claims (1)

[Scope of Claims] 1. A strainer used in a flow path for a liquid containing solids that precipitate as the temperature drops and melt and disappear as the temperature rises, the filter chamber having a vertical cylindrical shape and having an inlet and an outlet for the liquid. A cylindrical filtration element is fixed vertically inside the filtration chamber, and the liquid is arranged to pass from the inside to the outside, passing through the center of the filtration element. The rotary shaft is provided with a scraping means for scraping and dropping the solid matter adhering to the inside of the element, and a means for rotationally driving this shaft is provided to melt the solid matter scraped off into the inside of the heating chamber. A strainer characterized by having heating means. 2. The strainer according to claim 1, wherein the heating means is a coil that passes steam. 3. According to claim 1, a blade or screw is provided in the center of the heating chamber and is attached to a rotating shaft that is the same as or separate from the rotating shaft of the scraping means, and is configured to cause an upward flow of liquid within the heating chamber. Strainer as described. 4. The strainer according to claim 3, wherein a cylinder having a diameter smaller than the filtration element and having a liquid flow path at the bottom is provided around the blade or screw.