JPS62194441A - Apparatus for measuring non-newtonian property in pipeline - Google Patents

Abstract

PURPOSE:To make it possible to measure the non-Newtonian property of the fluid flowing through a pipeline by an on-line system, by measuring the difference pressure of a different diameter pipe part having three different diameters and comparing the calculated difference pressure value of the different diameter pipe part with an actually measured difference pressure value. CONSTITUTION:Measuring pipes S, M, L different in an inner diameter are interposed on the way of a pipeline main pipe X and connected by reducers R so as not to inhibit the flow of a fluid. An operator 2 operates the output values from the difference pressure gauges mounted to the measuring pipes S, L on the basis of the output value from the difference pressure gauge 1M mounted to the measuring pipe M having the intermediate inner diameter supposing that the fluid flowing through the main pipe is a Newtonian fluid. The obtained operated values are inputted to differential amplifiers 3L, 3S where the differences between said values and the actually measured values from difference pressure gauges 1L, 1S are amplified and outputted. Said differences show the shift from the Newtonian fluids in the measuring pipes S, L and, if the magnitude or the positive and negative thereof is known, the non-Newtonian property of the fluid flowing through the pipe can be judged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for measuring the non-Newtonian nature of pipeline transport fluids.

[Conventional technology]

Understanding the properties of the fluid inside a pipeline is an extremely important issue for operational purposes.

In recent years, for purposes such as reducing oil consumption, it has become necessary to transport highly concentrated coal slurries such as CWM and COM through pipelines. These high viscosity fluids exhibit non-Newtonian properties that do not follow Newtonian flow.Measurement of the non-Newtonian properties of such non-Newtonian fluids has conventionally been carried out by sampling a portion of the fluid from a pipeline and using a rotational viscometer, etc. The flow curve, which is the relationship between shear rate and shear stress, was determined using a rheology measurement device, and non-Newtonianity was determined based on the shape of this curve. However, such off-line measurements pose no problem if the rheological properties in the pipeline are always constant; When properties may change, the time from sample collection to obtaining measurement results becomes an issue. That is, it takes at least several 1° from sample collection to determination, and in the case of 1 determination, the fluid to be measured in the pipeline has been transported several kilometers away. When operating a pipeline, it is necessary to control flow rate and pressure according to changes in fluid properties, especially changes in viscosity.

Off-line measurements such as those described above cannot fully meet this demand.

On the other hand, as a method for measuring the properties of pipeline fluid online, there is a method of directly attaching a rotational viscometer or differential pressure viscometer to the pipeline.

In this method using a rotational viscometer, a cylindrical or conical rotor is inserted inside the pipe, and the rotor is rotated at a constant rotation speed by a motor outside the pipe. It is a method of measurement. Since this torque measurement value is proportional to the viscosity, the viscosity can be determined from this torque value.

However, this method has problems, such as the need to insert a structure such as a rotor into the pipeline, and the need to compensate for the influence of fluid flow within the pipe.

The method using a differential pressure viscometer involves installing a flow meter and a differential pressure gauge in the pipeline, continuously measuring the flow rate Q and pressure loss value ΔP, and measuring the apparent viscosity at a certain flow rate value using Hagen-Poiseuille's law. This is the way to do it. This method does not have the disadvantages of using a rotational viscometer as described above, but
Although the detected apparent viscosity is useful for knowing the tendency of increase/decrease in viscosity of the fluid, it is impossible to know the non-Newtonian property.

[Summary of the invention]

The present invention has been made in order to improve the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a measuring device that can measure on-line the non-Newtonian nature of a fluid flowing in a pipeline.

For this purpose, the present invention provides a pipe section with different diameters formed in the middle of a pipeline and having at least three different diameters, a differential pressure gauge for measuring the differential pressure of each of the pipe sections with different diameters, and A device that calculates a calculated differential pressure value of another pipe section with a different diameter based on a differential pressure value of one pipe section with a different diameter assuming a Newtonian fluid, and a difference between the calculated differential pressure value and the actual measurement from the differential pressure gauge. The basic feature is that it has a comparison device for comparing pressure values.

Here, the types of non-Newtonian fluids will be explained. Fig. 3 is called a flow curve, and the horizontal axis represents shear stress τ and the vertical axis represents shear rate n. In pipe free flow, it is generally expressed by the shear velocity and shear stress on the pipe wall surface, and these are defined as the following formula.

= LQ- in the case of Newtonian fluid) πR 7 = J scale 2, where Q: Flow rate R: Pipe radius ΔP: Pressure loss t: Differential pressure measurement interval R, t are known, so use a differential pressure gauge to calculate If Q is determined from ΔP and a flowmeter, n, and τ can be determined.In the case of Newtonian fluid, n.

The relationship between τ is expressed by the Hagen-Poiseuille equation as shown below.

Q=5R’ (ip) 8η The names and relationships of each curve shown in the diagram are shown in the formula below.

■Newtonian fluid ■Bingham fluid 1 = 1 (τ-τ.) η ■Power law fluid - r = 1τ・η n〉1: Pseudoplastic fluid n×1: Dilatant fluid ■East fluid with yield value; = 1 cτ −τ0)″ η However, η: Viscosity n: Rheological index τ0: Yield stress Now, calculate τ and i using a differential pressure meter and a flow meter, and use their ratio to determine η
Even if the fluid is known to be a Newtonian fluid, the flow curve can be determined unambiguously, but when the properties of the fluid in the pipeline are unknown, it is impossible to know the properties of the fluid and the flow curve. .

Therefore, in the present invention, pipe sections with different diameters are provided in at least three locations in the pipeline, Te and τ are measured at these three locations, and the measured values are compared with calculated values assuming a Newtonian fluid. It attempts to measure non-Newtonian properties.

〔Example〕

The present invention will be described in detail below based on the implementation details.

In FIG. 1, measurement tubes S, M, and L having different inner diameters are interposed in the middle of a main pipeline X, and constitute a diameter difference section. Each measuring tube S.

Differential pressure gauges 18+'M+''L are attached to M and L, respectively, and are configured to measure the differential pressure ΔP in the container tube.This differential pressure gauge 1 may be an ordinary differential pressure gauge, and the static pressure gauge 2 can be used as the differential pressure gauge 1. They may be combined to form a differential pressure gauge.The measuring tubes S, M, and L are connected by a reducer R so as not to obstruct the fluid flow.Also, the entire measuring tube is formed into a tapered shape. Different diameter pipe sections may be formed by providing differential pressure gauges at three locations spaced apart in the length direction.

The diameters of the measuring tubes S, M, and L are arbitrary as long as there is a diameter difference, but in this example, the inner radius RM of the measuring tube M is the same as the inner radius of the main tube X, and the shear rate is set to match that of the main tube. I'm letting you do it.

Note that one of the measurement tubes S, M, and L may be used as the main tube X. In addition, when a tapered pipe is used, a variety of configurations are possible, such as providing differential pressure gauges at one location on the main pipe X and two locations on the tapered pipe.

An arbitrary one output of the differential pressure gauge 1 is connected to the computing unit 2. In this embodiment, a differential pressure gauge 1M attached to a measuring tube M having an intermediate inner diameter is connected to a computing unit 2.

This calculator 2 calculates values in the other measuring tubes S and L based on the output value from the differential pressure gauge IM. At this time, calculations are performed assuming that the fluid flowing inside the pipe is a Newtonian fluid. In this embodiment, two arithmetic units 2L and 28 are provided to calculate values in the pipe and S, respectively.

Now, the differential pressure gauge 'ss'M! The signal EL t ”M which is the output from t converted into the pressure loss arrangement within the unit length
If I EB (EαΔPατ), the arithmetic unit 2L12
8, input EM, E, and XB' respectively.

Calculate EHXB No.7. here.

ΔP E α □ However, RM: Inner diameter of measuring tube M R8: Inner diameter of measuring tube S RL: Inner diameter of measuring tube This EMBL4. EMB♂ is a value derived from Hagen-Boiseuille's equation, taking into account the difference in diameter of the tubes M, S, and L, assuming that the fluid flowing through the tubes is a Newtonian fluid. If each point of these values EM, EMxBI4゜EMX B♂ is displayed on the graph showing the tn7-Anτ relationship in Figures 4 and 5, it will be on a straight line representing a Newtonian fluid with a rheological index of 11 = l. .

The above zMXB' and EMX Bs' are differential amplifiers 3L
.

3s, and here the difference between the differential pressure gauge IL and the actual measurement value from 1s is amplified and output. In the illustrated input terminal connection, the output of amplifiers 3L and 3s is 1L.

ε8 is expressed by the following formula.

a, = EL-EMX B,'・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・■! s=EM
X B6' -Es Song/Song...Song...
. . . The difference of -9ε8 indicates the deviation from the Newtonian fluid in the measurement tubes S and L. Therefore, 'L
If you know the magnitude and sign of l'8, you can judge the non-Newtonian nature of the fluid flowing inside the pipe.

Regarding the various non-Newtonian fluids mentioned above, 6LI88
Explain how it changes. First, let's consider the case of the power eastward fluid. The exponent n of the power east side fluid is called the rheological index, and is one index representing non-Newtonian property.

When the relationship between shear rate and shear stress is expressed on a double-logarithmic graph, it can be expressed by a straight line with an inclination depending on the index n, as shown in FIGS. 4 and 5. Further, in the figure, Newtonian fluid (n=1), εS, and δL are also shown.

88° is expressed by the following formula, and since BL and B are constants determined by the device, they take positive and negative values depending on the index n, and from Newtonian fluid with index n (ε8=0°ε, =0), deviation can be detected.

Month 1 ε1=(BLn-BL')EM・・・・・・・・・・・・
...■ and 1 ε8 = (B knee Bsn) EM...
...The case of zero-order Bingham fluid will be explained. The relationship between the flow rate and pressure loss of Bingham fluid is expressed by the following equation called the Packingham-Reyna equation, where the second and subsequent terms in parentheses are terms representing non-Newtonian properties.

If the minute term in the equation is omitted and 88° 1L of Bingham fluid is expressed, it can be expressed as in the following equation.

6L=4-(do)(BL-Bff)E...
...■ω' =” (-) (B,;-B,) Eya...
・・・・・・・・・■S 3 τω One, since BS is a constant determined by the device, it takes a value proportional to the yield value n, and is a Newtonian fluid (
τo=0. In other words, deviation from 6L=6s=0) can be detected. The table below summarizes the positive/negative relationship between 8L and @s of each fluid explained above.

In reality, the fluid inside a pikeline is rarely the ideal Bingham fluid or the east side fluid as described above, but rather the east side fluid with a yield value that combines the properties of both, or the east side fluid with a complicated curve. There are many cases.

In this case, depending on the combination of the rheological index n and the yield chamber τ0, it is not possible to uniquely determine whether the values of aL and ε8 are positive or negative, but for any value, aL and ag
Both of these do not become zero at the same time, and can clearly be distinguished from a Newtonian fluid (−L=68=0.0 at the same time).

In this embodiment, the above-mentioned outputs aL, ε8 are further processed by the multiplication/division units 4L, 4. After dividing EM and applying an appropriate scaling constant, display 5L and 5B
I am trying to display it in The arithmetic units 4L and 4s output control signals in addition to those for display.

FIG. 2 shows another embodiment, in which an arithmetic processing device 7 such as a microprocessor is used. Here, the outputs EL, EM, and Es from the differential pressure gauge (not shown) are expressed as A/
After being digitized by the D converter 6, - the arithmetic processing unit 7
It is processed by This process is the same as the process performed by the constant arithmetic unit 2, the differential amplifier 31, and the multiplication/division arithmetic unit 4 in the embodiment shown in FIG.

〔Effect of the invention〕

As explained above, 1. According to the measuring device of the present invention, the non-Newtonian nature of the fluid in the pipeline can be measured online, and changes in the properties of the fluid can be detected sequentially, so that the pipeline operation can be carried out efficiently. be able to.

Brief explanation of the pathogenesis Figure 1 is a block diagram showing one embodiment of the present invention, Figure 2 is a block diagram showing another embodiment, and Figure 3 is a flow curve showing the properties of Newtonian fluid and non-Newtonian fluid. 4 and 5 are flow curve diagrams for explaining the operation of the embodiment.

DESCRIPTION OF SYMBOLS 1... Differential pressure gauge, 2... Constant operator, 3... Differential amplifier, 4... Multiplication/divider operator, 5... Display, 6...
A/D converter, 7... Arithmetic processing unit.

Patent applicant Nippon Kokan Co., Ltd. Inventor Hideo Hayashi
Shigeto Otomo
Yasu Hosaka Iroma
O 1) Shun - Representative Patent Attorney
Yoshihara Sho Sanmon High School
Kiyodo Hashi Attorney Yoshihara
Hiroko No. 3 Figure 'Z:'0 +! - 4th Zurikkanmenryoku (τ) Fig. 5

Claims (1)

[Scope of Claims] A pipe section with different diameters formed in the middle of a pipeline and having at least three different pipe diameters, a differential pressure gauge for measuring the differential pressure between the pipe sections with different diameters, and a differential pressure gauge for measuring the differential pressure between the pipe sections with different diameters; A device that calculates a calculated differential pressure value of another different diameter pipe section from a differential pressure value of one different diameter pipe section assuming Newtonian fluid; A comparison device for comparing non-Newtonian properties in a pipeline.