JPS5819511B2 - Method for preventing solidification of slurry-like cargo and ship for transporting slurry-like cargo - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing solidification of slurry cargo during transportation, and a transport ship for slurry cargo to which the method is applied.

When pulverized iron ore, pulverized coal, or other pulverized solids are loaded into a ship's hold as a slurry and transported, these pulverized solids have a higher specific gravity than the mother liquor, so they settle in the hold during a long voyage. It is then consolidated and hardens at the bottom to form a hard nodule.

After being transported by sea, it is difficult to unload the hard packed lumps using a pump or the like at the port of arrival.

Therefore, since the cargo is unloaded in a slurry state using pumps and piping at the arrival port, it is necessary to devise ways to prevent the powder from solidifying in the ship's hold during the voyage.

Conventional techniques to deal with this can be roughly divided into the following two types: (1) Adding emulsifiers or dispersants to slurry-like cargo to prevent sedimentation.

■Continues strong agitation during voyage to prevent sedimentation.

However, these conventional methods have some problems, and it is desired to develop new techniques that solve these problems.

That is, the emulsifier and dispersant produced by method (2) contain heavy metals, which cause corrosion of equipment and air pollution in the subsequent refining and combustion steps.

Furthermore, in order to prevent solidification of slurry-like cargo, it is insufficient to prevent particles from settling.

In other words, even if the particle size is reduced to several microns and emulsifiers and dispersants are added to prevent particle agglomeration for the purpose of preventing sedimentation, if the specific gravity of the particles is greater than that of the liquid, gravity will After a long period of time, the particles inevitably settle to the bottom and become solid.

Moreover, if the compression process continues, the gaps between the particles become extremely small in proportion to the particle size, and although the speed at which the liquid is squeezed out is slow, once it is squeezed out, it becomes more solid. .

Furthermore, in the method (2), it is extremely difficult for practical workers to mechanically stir the amount of slurry reaching several tens of thousands of tons per transport ship, as it requires enormous power.

The present invention aims to solve the above-mentioned problems in the conventional technology, and aims to provide a practical method that can effectively prevent solidification of slurry-like cargo, and a transport ship applying the same. .

The first step in obtaining the present invention capable of achieving this objective began with an analysis of the solidification phenomenon of slurry-like cargo.

Inside the ship's hold, the powder first settles, then the powder grains pile up on top of each other, and are eventually compressed by the powder's own weight, eventually forming a solidified aggregate.

This process can be roughly divided into two physical phenomena: a process in which particles settle without contacting each other, and a process in which particles are compressed by their own weight while in contact with each other.

In the latter compression process, as the layer of particles is compressed, the liquid between the particles is squeezed out through the narrow gaps.

The speed of this compressive deformation depends on the speed at which the liquid is squeezed out.

Therefore, to prevent solidification of slurry cargo,
It is essential to consider the above two processes, especially the compression process.

The speed of the compression process can be controlled by forcibly replenishing the amount of liquid squeezed out from the particle gaps from outside.

For example, by replenishing an amount of liquid equal to the amount of liquid squeezed out, the progress of compression can be stopped and solidification can be prevented.

In this case, as the liquid used to control the compression speed, it is preferable to use the supernatant liquid that comes out on the top of the lead wire sedimentation material.

This is because there is no need for extra liquid and the piping system can be used to suck up excess liquid when loading slurry cargo. explain.

When powdered solids are transported by ship in the form of a slurry, a portion of the water added to form the slurry does not need to be transported and should be discarded at the loading port or returned to shore.

In particular, the heavy oil or crude oil added to make pulverized coal into a slurry state is difficult to obtain in coal-producing areas, so the surplus used for loading must be returned to the loading port on land.

If the sedimentation speed of the particles is high, the liquid and particles will separate into upper and lower parts during the loading time, and the excess can be returned by suctioning the supernatant.

On the other hand, if the sedimentation rate of the particles is low, this can be achieved by suctioning the liquid through a porous filter as the liquid supply section.

As understood from the above description, the present invention has the following features.

That is, first of all, the first invention (well, when transporting a powdery solid in a slurry state, by supplying the supernatant liquid of the slurry cargo into the sediment at the bottom, the sediment is compressed and turned into a solid state. To prevent it from hardening.

In addition, a second invention provides a liquid supply section that is arranged at the bottom of a hold that accommodates slurry-like cargo, and a supernatant liquid of the slurry-like cargo in the lead line is transferred to the liquid supply section [pipe line for transporting the slurry cargo] through a pump. It is distinctive in that it has been established.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows changes in the state of slurry cargo when the method of the present invention is adopted.

■ to ■ indicate stages of state change.

Reference numeral 6 denotes a boat hold, on the bottom of which a porous filter 7 is attached, and piping is installed that passes through a collection chamber 8 and a valve 9 to a pipe 10.

In stage (3), the slurry 14 supplied from the pipe 11
is separated into a supernatant 12 and a powder precipitate 13 in a boat 6.

When the particle size of the powder is minute, this separation interface is not clear.

If separation is evident, the supernatant 12 is pumped out by hanging a suction tube from above.

In general cases where sedimentation separation is slow and unclear, tube 10
Excess liquid can be sucked out by a pump from downstream of the pump.

At stage (2), loading of the slurry 14 has been completed and discharge of excess liquid has also been completed.

Stage ■ is a state in which sedimentation has further progressed after a certain period of time has passed after leaving port.

The supernatant at this stage (■) is 15.

At this time, the sediment below is not compressed and is in a soft state that can be unloaded onto land using a pump if necessary.

As the voyage time passes and the stage progresses from stage ■ to stage ■, the lower sediment undergoes compression deformation up to position 16.

Therefore, the supernatant liquid depth increases from 15 to 16.

At this stage (2), the sediment becomes hard and clogged, making it impossible to suction it with a pump and unload it.

Before reaching stage (2), if liquid is supplied from the filter 7 through the pipe 10, valve 9, and collection chamber 8 as shown in stage (2), the precipitate can return to the state of stage (2).

At this time, the amount of liquid supplied from the filter 7 is the liquid level 16 and 1
This is a difference of 5.

This can be done by removing a portion of the supernatant liquid.

The minimum flow rate required to sustain stage (2) can be determined from the value by measuring only once the temporal change in the difference between liquid depths 16 and 15 from stage (2) to stage (2).

Next, a ship for transporting slurry cargo to which the above immobilization prevention method is applied will be explained.

Figures 2 to 6 show an example of a transport ship, where Figure 2 is an overall view of the transport ship, Figure 3 is a sectional view taken along line a-a, and Figure 4 is a cross-sectional view of the transport ship.
The figure shows a detailed view of the filter installed in the bottom of the hold, Figure 5 is a cross-sectional view of a pipe that passes horizontally through the center of the sediment and supplies a liquid to prevent solidification, and Figure 6 shows how to suck out the supernatant liquid. FIG.

The transport ship 20 is equipped with one or a large number of liquid-tight vessels 6, but even in the case of multiple vessels, each of the vessels 7 to 24 (excluding 12, 13, 15° 16) and 33, which will be described below,
．． It is equipped with 34, 36 and 37 parts and devices, each of which performs the same function.

In order to load the slurry into the cargo hold 6 provided on the transport ship 20, the slurry loading pipe 11 and the excess liquid return pipe 28 are each connected to corresponding equipment on land.

It is also possible to provide offshore equipment in the middle of this connecting pipe.

The slurry 14 is loaded into the boat 6 from the slurry loading pipe 11 to a specified depth.

During loading, from filter 7 to valve 9, pipe 10, valve 2
4. The flow path through valve 22, pump 26 and valve 27 to pipe 28 is opened, and pump 26 is activated.

This starts the layering of excess liquid.

Once a certain amount of loading has been reached, the valve 23 is further opened and suction from the perforated tube consisting of the tube elements 36, 37 is also added.

Above is the time from loading to departure. When the clear liquid is separated, suction from the flow path from the bell mouth 18 to the valve 21 is also performed in parallel.

Here, as the pump 26, a model with specifications capable of suctioning at a sufficient degree of vacuum is selected.

Further, the pore diameters of the filter 7 and the pipe member 36 are equal to or smaller than the minimum particle diameter of the powder.

do.

This allows the particles flowing into the pump 26 to be extremely small and in small quantities.

After loading the slurry, the pipes 11 and 28 are disconnected from the land side, and the transport ship 20 leaves the port and continues its voyage.

After a certain period of time has elapsed after leaving the port, the slurry in the vessel 6° separates into a supernatant 12 and a sediment 13.

During this time, changes in the liquid depth of the supernatant 12 are recorded, and from this data the amount of liquid to be supplied necessary to prevent solidification is calculated,
The flow rate is set in the pump 26.

Then, valves 22 and 27 are closed and valve 25 is opened. Release, bell mouth 18 to valve 21, pump 26, valve 25, valve 23
The pipe line leading to the porous pipe (36, 37) is opened.

At the same time, the pipe line leading to the filter 7 via the valve 24 is opened to continue supplying the liquid from the bottom.

By continuing to supply this liquid, solidification of the precipitated powder is prevented and the slurry of the cargo is maintained in a soft state that can be unloaded by the pump.

To unload the slurry, the valve 34 of the suction hole 33 provided at the bottom of the boat 6 is opened, and the slurry pump 32, pipe line 35,
It can be started by opening 1.

It is also possible to include offshore unloading equipment (floating type piping connection) in the middle of the unloading pipeline 30.

Note that it is also possible to continue supplying the liquid to prevent solidification even while unloading continues.

As described above, according to the present invention, since the supernatant liquid of the slurry-like cargo is supplied into the sediment at the bottom,
The powder particles forming the slurry cargo can be prevented from settling, piling up, and forming solidified aggregates.

Furthermore, in the present invention, a liquid supply section is provided on the bottom of the ship, and the slurry supernatant liquid is sent to this liquid supply section via a pump, so that solidification of the precipitate due to sedimentation and compression of the solid particles forming the slurry is prevented. It can be effectively prevented.

Further, in the present invention, since the slurry supernatant liquid is simply sent to the liquid supply section at the bottom of the plumb line, the structure of the ship can be significantly simplified.

No other special liquids or equipment are required.

Therefore, slurry cargo can be transported to the destination at low cost while preventing solidification of powder particles.
Moreover, at the destination, the entire amount of slurry cargo within the lead line can be unloaded continuously without any hindrance.

[Brief explanation of drawings]

Fig. 1 is a diagram showing changes in the state of slurry cargo when the method of the present invention is adopted, Figs. 2 to 6 show an example of a transport ship according to the present invention, and Fig. 2 is an overall view of the transport ship. , Fig. 3 is a sectional view taken along line a-a, Fig. 4 is a detailed view of the filter, Fig. 5 is a sectional view of the liquid supply pipe for preventing solidification, and Fig. 6 is for sucking out the supernatant liquid. It is a sectional view of a bell mouth. 6... Ship, I... Filter, 12
...supernatant liquid, 13 ...precipitate, 20
...Transport ship, 26 ...Pump, 36
, 37... pipe member.

Claims (1)

[Claims] 1. When transporting powdered solids in a slurry state, by supplying the supernatant liquid of the slurry cargo into the sediment at the bottom, the sediment is compressed and solidified into a solid state. A method for preventing solidification of slurry-like cargo. 2. A liquid supply section is disposed on the bottom of a boat hold that accommodates slurry-like cargo, and a pipe line is provided to send the supernatant liquid of the slurry-like cargo in the boat hold to the liquid supply section via a pump. A ship transporting slurry cargo.