JPS6283926A - Transporting method for solid state particle - Google Patents

Abstract

PURPOSE:To reduce energy consumption while to reduce abrasion of a conduit, when pressure feeding slurry of solid state particles and aqueous medium through the conduit in a spiral flow, by adding 1-7wt% of gas against the aqueous medium. CONSTITUTION:When pressure feeding slurry of solid state particles and aqueous medium through a conduit in spiral flow, 1-7wt% of gas against the aqueous medium is added. Consequently, the slurry phase and the gas phase will form respective spiral flows and travel through the conduit while twisting each other. Here, the slurry phase spiral flow will sustain over a longer distance when compared with the case where gas is not added. In other word, the slurry phase 1 in the conduit will travel in zigzag as a whole while performing spiral motion of individual water molecule and solid state particle in that phase and the gas phase 2 will travel in zigzag while entangling with the slurry phase 1 and collecting bubbles. Consequently, sedimentation of solid state particles can be prevented resulting in reduction of energy consumption and prevention of abrasion.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for transporting solid particles through pipes.

BACKGROUND OF THE INVENTION Methods for transporting solid particles by 'f:'t11 using high-velocity air streams, ie pneumatic transport methods, are already known.

In this method, compressed air is blown into the pipe through a thin nozzle to forcefully transport the solid particles, but the air inside the pipe becomes a turbulent flow, and the solid particles repeatedly collide with the inner wall of the pipe in a turbulent state. Since the solid particles are transported at high speed, there is a disadvantage that not only is there a large energy loss, but also that the inner wall of the pipe is rapidly worn out if the solid particles have high hardness. Furthermore, since a large amount of compressed air is used, energy consumption is also large.

There is also a method of transporting solid particles through a pipe as a water slurry, but although this method consumes less energy, if the solid particles have a large specificity or particle size, they will settle and accumulate at the bottom of the pipe. It has the disadvantage of easily clogging the tract.

Problems to be Solved by the Invention An object of the present invention is to provide a method capable of transporting solid particles with low energy consumption and less wear on pipes by eliminating the drawbacks of conventional solid particle transport methods. shall be.

Means for Solving Problems with the Invention The method for transporting solid particles according to the present invention includes the following steps when pumping a slurry of solid particles and an aqueous medium through a pipe in a spiral flow state:
It consists of adding 1-7% by volume of gas to the aqueous medium.

Initially, the inventors proposed that when a slurry of solid particles and wood was pumped through a pipe, the slurry would turn into a J! An attempt was made to create a helical flow (a flow that moves in the axial direction of the pipe while rotating around the pipe axis) by applying an I motion, and to suppress sedimentation by causing the solid particles in the flow to rotate as well. When the pipe line was short, the expected effect was shown, but when the pipe line was long, the rotational linkage gradually decreased by 9A, and eventually solid particles were unavoidable to settle.

However, surprisingly, when pumping a slurry of solid particles and an aqueous medium through a pipe in a spiral flow state, 1 to 7 of the aqueous medium
% by volume of gas, the slurry phase and the gas phase form separate spiral flows, and both phases proceed through the pipe in a state that is twisted around each other like a rope, causing the slurry phase to form a spiral flow. We found that the flow persisted over longer distances than without the addition of gas.

Figure 1 shows this state as a model.In the slurry phase l in the pipe, the individual water molecules and solid particles in that phase are spirally interlocked, and the overall meandering, The gas phase 2 turns (meanders) in a state where the gas bubbles are gathered and become entangled with the slurry phase 1.

When transporting liquids through pipes, if air or other gas gets mixed into the pipe, it usually causes undesirable phenomena such as blocking or cavitation, so it is common sense to avoid mixing as much as possible. When doing so, extremely unique phenomena occur, as in Book L.

The addition rate of gas to the aqueous medium is in the range of 1 to 7% by volume. When it is less than 1% by volume, the effect is not sufficient, and when it is more than 7% by volume, the gas accumulates in a layer at the top of the pipe and stagnates, and no dR/jc movement occurs. Preferably 2
~5% by volume.

As shown in Fig. 2 and Fig. 3, which is a cross-sectional view taken along the line A-B, the method of making the slurry of solid particles and aqueous medium into a spiral flow state in the pipe is to Slurry is fed into a cyclone-type feeder 4 having a cylindrical portion with a large inner diameter through a nozzle 5 attached in the tangential direction of the cylinder, and the swirling flow is generated by the cone portion 41 of the feeder 4 and then flows up the pipe. Alternatively, only water is fed from the nozzle 5 to the feeder from the tangential direction to form a swirling flow, and solid particles are fed separately from the solid particle supply pipe 6 inserted from the central axis direction of the feeder. A method of forcibly forming a spiral air flow by mixing it with the swirling flow of air and feeding it into a pipe, or a method described in Japanese Patent Application Laid-open No. 60-58723 "A device for generating a stable spiral air flow in a pipe". Methods such as applying a device like this to spontaneously form a spiral flow can be adopted.

The gas may be mixed with water from the beginning and supplied to the feeder, or a gas nozzle 7 may be provided separately from the nozzle 5, and a 93 m
The gas may be introduced into the feeder from any direction, and air is usually used as the gas.

The distance over which solid particles are stably transported varies depending on the size, specific gravity, etc. of the solid particles, but the smaller the size of the solid particles and the smaller the difference in specific gravity between the solid particles and the aqueous medium, the longer the transport distance becomes.

For example, when transporting coal grains, water may be used as the aqueous medium when transporting small coal grains, but when transporting large coal grains, fine coal powder is mixed with water [7] By using a raised aqueous medium as an aqueous medium to reduce the difference in specific gravity with large coal grains, it can be stably transported over longer distances.

Examples and Comparative Examples A device as shown in Fig. 2 (the inner diameter of the cylindrical part of the feeder is 180 mm, the inner diameter of the conduit made of a transparent plastic tube is 3
8 mm, length 20 m) was installed, and 2.8 m/min of water was sent from nozzle 5, and the flow rate of ice in the pipe (
Water flow rate/pipe cross-sectional area): 2.47 m/sec], air at 2% of the wood flow rate was supplied from the gas nozzle 7, and coal particles with an average particle size of 8 mm were fed from the solid particle supply pipe 6. The behavior of wood, air, and coal particles in the pipeline was observed.

As a comparative example, a case where only water and coal were supplied without air was also observed.

The meandering wavelength (the distance between the ridges) tended to gradually decrease as it moved away from the entrance, that is, there was a tendency for the M-decay of the swirling motion, but the degree of attenuation was smaller when air was added. Ta.

In the case of only water and coal, a portion of the coal began to settle from around 8 m from pipe man 11, whereas in the case of mixing air, the entire amount of coal was transported to the pipe exit.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention in a model manner,
FIGS. 2 and 3 are diagrams for explaining the experimental apparatus of the present invention.

Claims (1)

[Claims] A method for transporting solid particles, which comprises adding gas in an amount of 1 to 7% by volume of the aqueous medium when pumping a slurry of solid particles and an aqueous medium through a pipe in a spiral flow state.