JPH075152B2 - Tank for solidifying and storing high pour point substances - Google Patents

Description

Detailed Description of the Invention

 Purpose of the invention

[Industrial applications]

The present invention relates to an improvement of a storage tank for storing high pour point substances such as crude oil, heavy oil, asphalt, and naphthalene in a solidified state.

[Prior art]

When the contents of the tank in which the high pour point substance is solidified and stored is discharged, generally, steam is supplied to the bottom heater to heat and melt and liquefy. However, the soul of the solid contents (hereinafter simply referred to as “solidified oil”) that remained in the upper layer during the progress of melting lost the support of the tank wall and fell.
May damage equipment such as the bottom heater. As a countermeasure against this, for example, a heater is provided along the side wall of the tank, and by melting the solidified oil also from the side wall, the pressure at which the solidified oil in the bottom part melts and thermally expands is released, and the solidified oil settling is received on the bottom heater. Providing a member to protect the heater has been proposed (Japanese Patent Publication Sho 57).
-183990). However, it is not preferable to provide the heater on the side wall because it complicates the structure of the tank and increases the construction cost and the operation cost. Especially, when it is applied to an existing solidified storage tank, a major modification is required.

[Problems to be Solved by the Invention]

A first object of the present invention is to solve the above-mentioned problems and to provide a solidified storage tank having a structure capable of preventing an impact caused by sedimentation and fall of solidified oil when a high pour point substance is melted. A second object of the present invention is to provide a solidified storage tank which can be constructed with a slight modification to the existing solidified storage tank and therefore at low cost. Structure of the invention

[Means for solving problems]

Referring to the drawings, as shown in FIGS. 1 to 3, a solidified storage tank for a high pour point substance according to the present invention has a net 3 substantially horizontally inside a tank 1 having a bottom heater 2. Limit the size of the unmelted solid sediment formed by melting the solid high pour point substance in one or more stages,
This is characterized in that the above-mentioned solidified oil is prevented from impacting by settling and dropping. The net 3 is supported by hooks 5 on the inner wall of the tank and / or a plurality of columns 4 provided in the tank. The stanchions are usually located in the center of the tank and concentric with the stanchions, and therefore they are used. The hook 5 may be provided on the inner wall of the tank, and the net may be stretched over the entire horizontal cross section of the tank. In the illustrated example, the net is stretched in three stages, but of course, one stage, two stages, or four or more stages may be provided. The material of the net 3 may be synthetic fiber such as polyamide or glass fiber or inorganic fiber, but use a metal wire rope with high thermal conductivity in order to prevent melting of the high pour point substance. Is advantageous. For the material, select one that has the highest corrosion resistance. The base end of the column 4 is brought into contact with the bottom heater 2 at the bottom of the tank,
Alternatively, a mode in which the net 3 made of a metal wire rope having a high heat conductivity is stretched is preferably provided in close proximity to the net 3. The structure of the mesh 31 of the net 3 can be a desired shape such as a honeycomb shape or a rhombus shape, as well as a spider web shape having branch points 32 as illustrated. The point is to prevent large sediments from forming. As a guide for determining the size of the mesh and the number of steps of the net, for example, when a spherical solid of C heavy oil with a diameter of 1 m falls in C heavy oil with a height of 12 m, the final settling velocity of the solid is 0.88. It becomes m / sec and the load at the time of collision is estimated to reach 650kg. The net 3 is preferably provided with a plurality of buoys or floats 6 at appropriate places. This is because, when the high pour point substance solidifies, it contracts and exerts a downward force on the net 3, so that the net is made to be convex upward so as to absorb this. The buoy or float 6 may be a hollow metal body, but a molded product of a foamed synthetic resin having a specific gravity of 0.6 or less, heat resistance and corrosion resistance, and moderate strength is advantageous because it is easy to manufacture. Is. Specific examples of the foam synthetic resin include polyurethane, phenol, and cellulose acetate. In the figure, reference numeral 7 is a delivery pipe for molten liquid.

[Action]

When the contents are discharged from the solidified storage tank of the present invention, steam is passed through the bottom heater 2 to heat the solidified oil 8 around the heater. At the same time, the heat of the heater is transferred to the net 3 through the support columns 4, and the solidified oil in the portion in contact with the net is melted to become the molten oil 9.
This situation is as shown in FIG. 4 (at the time of solidification storage) and FIG. 5 (at the start of heating). The higher the thermal conductivity of the net 3 and the pillar 4, the faster the melting of the solidified oil around them. The thermal expansion and pressure increase caused by the solidified oil melting at the bottom of the tank cause the net 3 and the support 4
Because the surrounding area is molten, it easily escapes to the upper part. The solidified oil mass 81 remaining in the upper layer of the tank shown in FIG.
It is supported by the net 3 and settles for the first time when it becomes large enough to pass through the mesh 31 of the net 3. Therefore, the large solidified oil does not settle as it is, and the impact due to dropping does not occur. At this time, in a preferred embodiment in which the nets 3 are provided in multiple stages, the solidified oil mass 81 that has dropped through the upper mesh 31 hits the lower net, so the sedimentation speed becomes slower and a smaller mass is formed. , Settles gently. By setting the mesh size of the lower net smaller than that of the upper net, it is possible to control the size of the lump of solidified oil that falls. In this way, the melting progresses, and all becomes the molten oil 9 as shown in FIG. Effect of the Invention The solidified storage tank of the present invention, when paying out the high pour point substance that is the content, heats and melts it by the bottom heater while preventing a large lump of solidified oil from falling down by a net, You can do it safely. By using a wire rope having high thermal conductivity as the net, the melting time can be shortened. In the event of an earthquake when the solidified oil is in a floating state during heating and melting, the net also serves to prevent the solidified oil mass from colliding with the columns and the tank side plates. This netted solidification storage tank has the advantage that it can be constructed at low cost because it has a simple structure and can be provided with a slight modification, especially when applied to the existing solidification storage tank with a bottom heater. is there.

[Brief description of drawings]

1 to 3 show a typical example of a tank for solidifying and storing a high pour point substance of the present invention, in which FIG. 1 is a plan view showing the inside without a lid, and FIG. The drawing is a cross-sectional view, and FIG. 3 is an enlarged explanatory view of a net. 4 to 7 are conceptual cross-sectional views for explaining the action of the solidified storage tank of the present invention. FIG. 4 shows the solidified storage, and FIG. 5 shows the initial stage of heating and melting. Fig. 6 shows the stage of heating and melting, and Fig. 7
The figures show the stages when the melting is complete. DESCRIPTION OF SYMBOLS 1 ... Tank, 2 ... Bottom heater 3 ... Net, 31 ... Mesh, 32 ... Branch point 4 ... Strut, 5 ... Hook 6 ... Buoy (or floating), 7 ... Discharge pipe 8 ... Solidified oil, 9 ... Molten oil

Claims (5)

[Claims] 1. A tank having a bottom heater is provided with a net substantially horizontally in one or more stages to limit the size of unmelted solid sediment produced by melting a part of a solid high pour point substance. A tank for solidifying and storing a high pour point substance characterized by the above. 2. A net, and / or an inner wall of a tank.
The tank according to claim 1, which is supported by a column provided in the tank. 3. A tank according to claim 1, wherein the net is formed of a wire rope made of a material having high thermal conductivity and corrosion resistance. 4. The tank according to claim 1, wherein a plurality of floats or buoys are attached to the net so that the net floats upward in a molten state of the high pour point substance. 5. The tank according to claim 4, wherein the float or the buoy is made of a foamed synthetic resin having a specific gravity of 0.6 or less and having heat resistance and corrosion resistance.