JPS5942769B2 - Chemical injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chemical injection method in which a water glass-based solidifying chemical is injected into soft or leaky ground (hereinafter simply referred to as "ground") to solidify or stop water (hereinafter simply referred to as "solidification"). The present invention relates to a device, and more particularly to a chemical injection method and device using carbon dioxide gas as a reactant for water glass.

Conventionally, when consolidating the ground, aqueous water glass solution and its hardening agent were mixed and injected in a liquid-liquid or solid-liquid state, but a method using carbon dioxide gas as the hardening agent was developed. As a result, chemical solutions were mixed and injected in a gas-liquid state.

When injecting carbon dioxide gas into a water glass aqueous solution,
Unless the relationship between the alkali content of water glass and the equivalent amount of carbon dioxide gas is within a certain range, it is impossible to form a uniform solid that is always in the same state. .

In known construction methods, the combined flow rate of water glass aqueous liquid is almost the absolute amount, whereas for carbon dioxide gas, even if the combined flow rate is constant, it changes when the pressure in the ground changes. The amount of carbonic acid fluctuated widely, and therefore the ratio to water glass was not constant (this resulted in a defect that caused variations in the quality of the gelled product produced by this reaction).

An object of the present invention is to form a uniform solid by always injecting an absolute amount of carbon dioxide gas to be mixed with the amount of water glass at a substantially constant ratio.

According to the present invention, the above object is to combine the absolute flow rates of the water glass aqueous solution and the pressurized carbon dioxide gas at a constant ratio regardless of changes in ground pressure (when injecting the water glass aqueous solution and pressurized carbon dioxide gas into the ground). This is achieved using the chemical injection method.

Furthermore, an example of a device for realizing the above purpose is as follows.
In a chemical liquid injection device comprising a water glass storage tank connected to an injection pipe inserted into the ground and a carbon dioxide gas storage tank connected within the multiple pipes, pressure fluctuations are detected between the carbon dioxide gas storage tank and the injection pipe. A liquid drug injection device provided with the device can be presented.

The present invention will be explained in detail below.

In the chemical injection method, the pressure in the ground is rarely constant from the start to the end of the injection, and the pressure in the ground constantly fluctuates depending on the consolidation state of the ground during the chemical injection process.

In liquid-liquid or solid-liquid chemical injection, even if there are pressure fluctuations in the ground, the absolute flow rate ratio of liquid-liquid or solid-liquid does not change much, and the rotation speed of the injection pump cannot be adjusted. By measuring, it is possible to keep the injection amount ratio constant relatively easily.

That is, the ratio of injection amounts itself corresponds to the ratio of absolute amounts.

Therefore, by combining the water glass aqueous solution and the reactant aqueous solution at a constant flow rate, it is possible to obtain a solidification effect due to a constant reaction.

However, when injecting carbon dioxide gas into a water glass aqueous solution, it is relatively easy to maintain the volume ratio almost constant even if there are pressure changes in the ground. Although the flow rate itself is almost the absolute amount, as mentioned above, the carbon dioxide gas is
Even if the combined flow rate is constant, the absolute amount will fluctuate due to changes in ground pressure, causing non-uniform solidification.

Hereinafter, the present invention will be explained in further detail using the drawings.

1 to 3 are flow sheets specifically explaining the present invention.

In FIG. 1, carbon dioxide gas is pumped from a storage tank 1 while being controlled to a constant pressure by a pressure reduction regulating valve 2.

The changing pressure of the ground 4 can be sensed by the pressure fluctuation sensing device A, and carbon dioxide gas can be pumped at an approximate absolute flow rate corresponding to the ground pressure.

On the other hand, the water glass aqueous solution is sent from the storage tank 5 to the ground 4 through a pressure reduction regulating valve 6, a pump 7 whose rotation speed is adjusted, and a flow meter 8.

The water glass aqueous solution and carbon dioxide gas are combined at the upper end of the injection tube or at the end of the injection tube consisting of multiple tubes 9 and are injected into the ground 4.

Furthermore, a device as shown in FIG. 2 can be shown as a specific example of the device used in the present invention.

In FIG. 2, carbon dioxide gas is pumped from a storage tank 10 while being controlled to a constant pressure by a pressure reduction regulating valve 20.

The fluctuating pressure of the ground 40 is sensed by the carbon dioxide gas amount controller 40, and a plurality of automatic flow control valves 50, 50' connected in parallel each have a separate flow rate set in advance.
・・・・・・By operating to open or close,
Carbon dioxide gas can be controlled and pumped at an approximate absolute flow rate corresponding to ground pressure.

As the number of control valves 50, 50', . . . increases, the absolute flow rate of carbon dioxide gas is controlled more accurately.

The carbon dioxide gas pressure flow rate indicator 60 is an indicator for ground pressure and carbon dioxide injection gas injection capacity, and indicates or records the carbon dioxide gas feeding capacity and ground pressure, and checks the absolute flow rate of carbon dioxide gas from the correlation between them. It is for the purpose of

As in the case of FIG.
0, is sent toward the ground 140 via the flow meter 120.

In this way, the water glass aqueous solution and the carbon dioxide gas are combined at the upper end of the injection tube or at the end of the injection tube made up of multiple tubes 130 and are injected into the ground 140.

Further, as an example of the device used in the present invention, a device as shown in FIG. 3 can be shown.

In FIG. 3, carbon dioxide is supplied from a storage tank 200 to a pressure reduction regulating valve 210.
It is controlled to a constant pressure and fed under pressure.

The changing pressure of the ground 230 is transmitted to the graphic calculator 250 by a current signal generated from the pressure transmitter 240.

On the other hand, the pressure difference before and after the flow meter 260 is measured by three valve manifolds 270, 270/.

270, the differential pressure transmitter 280 transmits the signal to the switching operator 290.

By adjusting the calculation results of both calculation units 250 and 290 with the flow rate indicating controller 300 and operating the automatic flow rate control valve 310, it is possible to continuously pump a constant absolute flow rate in accordance with the ground pressure.

As in the case of FIG. 1, the water glass aqueous solution is sent from the storage tank 320 to the ground 230 through the pressure reduction regulating valve 330, through the pump 340 and the flow meter 350.

In this way, the water glass aqueous solution and the carbon dioxide gas are combined at the upper end of the injection tube or at the end of the injection tube consisting of multiple tubes 360 and are injected into the ground 230.

As described above, the absolute flow rate of carbon dioxide gas can be preferably controlled using any of the devices shown in Figs. A solid is obtained.

In the case of FIG. 2, the absolute flow rate of carbon dioxide gas is continuously controlled in response to fluctuations in the pressure of the basin plate, so the error is extremely small compared to the intermittent control shown in FIG.

However, of course, in terms of equipment, the case shown in FIG. 1 is cheaper.

In order to inject the water glass aqueous solution and carbon dioxide gas, which are kept at a constant absolute flow rate, into the ground, it is possible to use a method such as a Y-shaped pipe where they are combined at the upper end of the injection pipe. If the glass is highly concentrated, it may solidify inside the pipe.

Therefore, by merging the injections near the end of the injection tube, a sufficiently satisfactory amount of solids can be obtained.

For this purpose, multiple tubes may be used and the water glass aqueous solution and carbon dioxide gas may be combined at the ends of the multiple tubes.

It is desirable to increase the gas-liquid contact area as much as possible at the end of the multi-tube used to increase reaction efficiency.

Specifically, water glass and carbon dioxide gas can be mixed in a mixing chamber at the end of multiple pipes and then injected, or water glass and carbon dioxide gas can be jetted into the ground from the end, and while mixing in the ground, the gas-liquid mixture is poured into the ground. You can take the method of infiltrating it inside.

Hereinafter, the present invention will be explained in further detail with reference to Examples.

Example 1゜ The following experiment was conducted using the apparatus shown in FIG.

First, a pressure-resistant mold with a diameter of 2 m and a height of 2 m was filled with sandy soil, a double pipe was inserted at a depth of 1 m, and carbon dioxide gas was introduced from the inner pipe and a water glass solution was introduced from the outer pipe.

A 25q6 aqueous solution of No. 3 water glass was used as the water glass, and it was fed at a discharge rate of 101 mm.

The carbon dioxide gas is kept at a constant pressure of 10'l/c4 with a pressure reducing valve, and the discharge pressure at the start of injection is 5.5kq/c! The amount of catering was set at 25 tln.

During the molding, the pressure at the outlet of the injection tube was changed by artificially controlling the pressure from the outside.

Six automatic flow rate control valves 50, 50', .

The controller sensed changes in ground pressure, and the commands activated six solenoid valves in response to ground pressure.

Figure 4A shows the changes in ground pressure, the corresponding flow rate of carbon dioxide gas, and the operating state of the solenoid valve at that time.

As is clear from FIG. 4A, since it is controlled by opening and closing a solenoid valve, the flow rate of carbon dioxide gas changes in stages in response to continuous fluctuations in ground pressure.

However, considerable accuracy can be expected by increasing the number of solenoid valves and skillfully combining the set flow rates of each valve.

Example 2゜The experiment of Example 1 was carried out using the apparatus shown in Figure 3. The round carbon dioxide gas flow meter 260 uses an orifice meter, and the differential pressure before and after the meter is led to the opening/closing calculator via three pulp manifolds. Ta.

A diaphragm valve was used as the automatic flow rate control valve 310, and the diaphragm valve could be operated continuously according to instructions from a flow rate controller to adjust the flow rate of carbon dioxide in response to changes in ground pressure.

As in Example 1, the flow rate of carbon dioxide gas was controlled not in steps but in a gradual sinusoidal curve.

Figure 4B shows the results obtained by converting the fluctuations in the carbon dioxide flow rate in Example 1 and Example 2 into a pressure of 5.5 ky/cA at the start of injection.

In other words, in the method shown in Figure 2, 5.5kq/d and 25t/
There is a maximum variation in flow rate of about 2.71 min for a constant flow rate injection of 2.7 min.

The ground pressure was rising (sometimes positive) and falling (sometimes negative), both of which caused errors, and the errors were about ±10%.

However, this error can be reduced by increasing the number of solenoid valves and how they are combined (this is obvious).

On the other hand, with the method shown in Figure 2, the error always rises and falls, creating a gentle sine curve, but the degree of error is approximately ±±.
There were about 4 people in charge.

[Brief explanation of the drawing]

1 to 3 are flow sheets specifically explaining the present invention. Figure 4A is a diagram showing the relationship between variations in ground pressure, carbon dioxide capacity, and the operating state of the solenoid valve, and Figure 4B is a diagram showing variations in carbon dioxide flow rate when using the devices shown in Figures 2 and 3. FIG. 1, 10. 200... Carbon dioxide storage tank, 2,
6゜20.100, 210.330... pressure reducing adjustment valve, 3.30, 80, 220... pressure gauge, 4
, 140° 230... Ground, 5, 90, 320
...Water glass aqueous solution storage tank, 7,140,340
...Pump, 8゜70.120,260,35
0...Flowmeter, 9°130.360...
・Multiple pipes, 40... Controller, 50,5
0'..., 310 automatic flow control valve, 60...
...carbon dioxide pressure flow indicator, 240 pressure transmitter, 2
50...Graphic calculator, 270°270
', 270"... Manifold, 280...
...Differential pressure transmitter, 290...Switching operator, 3
00...Flow rate indicator adjustment meter, A...Pressure fluctuation sensing device, ■...Carbon dioxide gas flow rate, ■...
...Ground pressure, θ...In the case of the device shown in Figure 2, ■
...For the device shown in Figure 3.

Claims (1)

[Claims] 1. In a chemical injection device comprising an injection pipe inserted into the ground, a water glass storage tank connected to the injection pipe, and a carbon dioxide gas storage tank connected to the injection pipe, the carbon dioxide gas storage tank and the injection pipe A pressure fluctuation sensing device is provided between the injection pipe and the carbon dioxide storage tank, and the pressure fluctuation sensing device sequentially connects an automatic flow rate control valve, a differential pressure transmitter, and an opening/closing valve downstream between the injection pipe and the carbon dioxide storage tank. The flow meter connected to the flow rate indicating regulator via the computing unit is connected to the same pressure transmitter (which is connected to the flow rate indicating regulator via the graphic computing unit), and the calculation results of both computing units are Based on this, the flow rate indicating controller operates the automatic flow rate control valve to control the absolute flow rate of carbon dioxide gas, and the water glass aqueous solution and the carbon dioxide gas are combined at a constant ratio and then injected. Injection device.