RU73485U1 - DENSITY-FLOW METER FLUID - Google Patents

Abstract

The proposal relates to the field of measuring technology and is intended to measure fluid parameters directly in the stream and can be used in oil and gas production, oil refining, petrochemical and other industries.

The utility model allows us to solve the problem of increasing the accuracy of measuring the density and flow rate of the liquid by applying the method of comparing the static parameters of the "reference" liquid with changing parameters of the working medium, and by using a calibrated pipeline with a sharp expansion of diameter, as a hydrodynamic type sensor, and minimize friction pressure losses by applying the surface with the smallest roughness in the horizontal measuring section.

The densitometer - flow meter contains an inlet pipe 1, an absolute pressure sensor 2, a vertical branch 3 with a diameter D, which is equipped with a lower (first) pressure sensor 4, an upper (second) pressure sensor 5 with a distance between them H = (1 ÷ 1,5) D, a sleeve 6 with a “reference” liquid, on which a thermometer of the “reference” liquid 7 is installed, and an additional pressure sensor 8, moreover, the pressure sensor 5 is connected by a pulse tube to the “reference” liquid 9 with the mentioned sleeve 6, and the lower pressure sensor 4 and additional pressure sensor 8 are on one level and pulse tubes are connected with the "reference" liquid 11 and 12 respectively to a first differential pressure sensor 13. The vertical branch 3 is installed thermometer liquid medium (liquid to be measured) 14. As the "reference" of the liquid used

a liquid that is in direct contact with the liquid being measured but not miscible with it, for example, organosilicon, having known coefficients of volume expansion and compression.

The horizontal branch 15 of the measuring column is made with a variable diameter and has a section 16 of a calibrated (single diameter) pipeline L ₁ with a smaller diameter D ₁ and a section 17 of a calibrated pipeline with a sharp increase in diameter D ₂ and a length L ₂ , where: L ₁ = (2 ÷ 3) D ₁ , and L ₂ = (3 ÷ 4) D ₂ , a . In section 17, the first pressure sensor 18 is located and the second pressure sensor 19 is located at a distance L = (2 ÷ 3) D ₂ at the same level. The pressure sensors 18 and 19 are connected by impulse tubes to the “reference” liquid 20 and 21, respectively, with the second the pressure difference sensor 22. Section 17 ends with the outlet pipe 23.

Absolute pressure sensor 2, a thermometer of the "reference" liquid 7, a thermometer of the measured liquid 14 and two pressure difference sensors 13 and 22 are connected to the recording unit 23 (BOI - information processing unit), which calculates the density of the measured liquid and its flow rate using the program laid down in it and provides a visualization tool, for example, a computer.

Description

The proposal relates to the field of measuring technology and is intended to measure fluid parameters directly in the stream and can be used in oil and gas production, oil refining, petrochemical and other industries.

Known devices for measuring the density of liquids in calculating the mass flow rate, belonging to the class of hydrodynamic densitometers (Kremlevsky PP, Flow meters and counters: Reference. - 4th ed., Revised. And add. - L.: Engineering. Leningrad, Department , 1989.)

A device for hydrodynamic density measurement is known, in which the medium velocity is measured by the method of zero pressure drop and the method of variable pressure difference measures the pressure head using a narrowing device under operating conditions of a possible continuous change. (Pat. RF №2273016, publ. 27.03. 2006)

The disadvantage of this device is that it is designed to measure the parameters of a homogeneous liquid that easily passes through a narrowing channel, but when measuring the parameters of a mixture with a different density of components, for example, oil, the smallest solid (asphalt-resin-paraffin) inclusions are deposited on the diaphragm - in place narrowing and it gets clogged (Joule-Thomson effect). Further measurement is not possible or occurs with errors.

Expanding type flow meters are also known, using as a pressure transducer a channel with a set of diffuser-confuser elements in a given sequence.

A device for measuring the flow rate of fluids (Pat. RU No. 2157973, publ. 10/20/2000). In the known device, the sensor in the form of a tubular body has an inlet pipe, a diffuser section, a section with a maximum cross section, a confuser section and an output pipe. Based on the differential pressure measured by differential pressure gauges in three sections, the flow rate is determined by known formulas using a calculator.

A disadvantage of the known device is the lack of automatic correction of the density of the "reference" liquid by temperature and pressure in relation to the operating conditions of the medium being measured, which affects the accuracy of the measurement of liquid parameters.

Known densitometer of liquid or gaseous media, containing a loop-shaped pipe of equal cross section, consisting of ascending, horizontal and descending branches, three pressure selectors installed respectively on these branches, two pressure difference sensors, absolute pressure sensor, temperature sensor, impulse tubes with " reference "fluid, perceiving the pressure of the working medium directly by the contact method, and the recording unit, while the densitometer is equipped with a temperature sensor of the" reference "fluid, and additional ADDITIONAL sampler pressure placed on the housing of the thermometer "reference" liquid temperature sensor, and pressure sockets are installed on the ascending, descending branches of the loop and tube sampler pressure placed on the thermometer casing at the same level in the lower hinge part. (Patent RU No. 67263 Density meter of liquid or gaseous media. Publ. 10.10.2007, Bull. No. 28)

The work of the known construction is based on the method of comparing the density of the "reference" fluid, which is in static, with the density of the working medium, which is in dynamics, which increases the measurement accuracy by an order of magnitude. The flow rate of the working medium is determined by the measured values

density of the working medium, friction losses along the length of the loop of the pipeline and its diameter.

The disadvantages of the utility model include the appearance of errors in measuring the flow rate of oil wells due to changes in the diameter of the pipeline due to the circular deposition of asphalt-paraffin inclusions in it. And since the flow measurement is determined depending on the friction losses and the diameter of the pipeline, their change entails measurement errors.

The objective of the claimed utility model is to increase the accuracy of measuring the flow rate and density of the working fluid.

This problem is solved by the fact that in the densitometer - a flowmeter of liquid media containing an inlet pipe, a measuring column made of vertical and horizontal branches, an outlet pipe, an absolute pressure sensor, a temperature sensor for the medium, pressure collectors mounted respectively on the vertical and horizontal branches, two pressure difference sensors, impulse tubes filled with a “reference” liquid, perceiving the pressure of the working medium directly by the contact method, a “standard” temperature sensor fluid and additional sampler pressure mounted on the sleeve, flooded "reference" liquid and the recording unit, the horizontal branch of the measuring column comprising a calibrated duct section length L _1, larger diameter D ₁ and the calibrated pipeline section length L ₂ from the sharp expansion of the diameter D ₂ at the output branch pipe, moreover, the ratio of squares , and the selection of lengths is carried out from the condition: L ₁ = (2 ÷ 3) D ₁ and L ₂ = (3 ÷ 4) D ₂ , and is equipped with a second pressure sampler located from the first pressure sampler at a distance L = (2 ÷ 3) D ₂ in a section with a diameter of D ₂ , while the first and second pressure taps are connected by impulse tubes filled with a “reference” liquid with the first pressure difference sensor, and the vertical

the branch of the measuring column with a diameter D is made with an inner coating that reduces resistance to the movement of the fluid flow and is equipped with a second - upper pressure tester located at a distance of H = (1 ÷ 1.5) D from the first - lower tester, and the first is the lower tester the pressure of the vertical branch and the additional pressure tester on the said sleeve are located at the same level and are connected to the second pressure difference sensor by impulse tubes with a "reference" liquid, and the upper one, the second pressure tester is connected to the wrinkled sleeve impulse tubes with a "reference" fluid. The density and flow rate of a liquid medium are determined respectively by the formulas:

,

,

where: ρ _W - the density of the liquid, kg / m ³ ;

ρ _tet is the density of the "reference" fluid, reduced to operating conditions, kg / m ³ ;

ΔР is the pressure difference between the column of the "reference" liquid and the sum of the hydrostatic pressure of the liquid medium and friction losses at the site of the height H of the pipeline, Pa;

g is the acceleration of gravity, m / s;

N is the distance between the upper and lower points of pressure selection, m;

M is the mass flow rate of the liquid medium, kg / s;

D ₁ and D ₂ - respectively, the diameters of the calibrated pipes of smaller and larger diameters, m;

ΔP ₁ is the pressure drop measured over the length L _{2 of the} pipeline D ₂ , Pa.

In addition, the absolute pressure sensor of the liquid medium, the temperature sensor of the liquid medium, the temperature sensor of the “reference” liquid, as well as two pressure difference sensors are connected to the recording unit.

The inner coating of the vertical branch of the pipeline with a diameter D can be performed by glass transition or using an epoxy layer or other material that reduces the resistance to movement of the fluid flow.

Figure 1 shows the device in statics.

The densitometer - flow meter contains an inlet pipe 1, an absolute pressure sensor 2, a vertical branch 3 with a diameter D, which is equipped with a lower (first) pressure sampler (sensor) 4, an upper (second) pressure sampler (sensor) 5 with a distance between them H = ( 1 ÷ 1,5) D, selected from the source: A.D. Altshul, L.S. Zhivotovsky, L.P. Ivanov “Hydraulics and aerodynamics”, M., Stroyizdat, 1985, sleeve 6 with “reference” the liquid on which the thermometer (temperature sensor) of the “reference” liquid 7 and the additional pressure selector (sensor) 8 are installed, and nickname (sensor) of pressure 5 is connected by a pulse tube with a "reference" liquid 9 to the mentioned sleeve 6, and the lower pressure sampler (sensor) 4 and an additional pressure sampler (sensor) 8 are at the same level and are connected by pulse tubes with a "reference" liquid 11 and 12, respectively, with the first pressure difference sensor 13. A thermometer (temperature sensor) of a liquid medium (measured liquid) is installed on the vertical branch 3 14. A liquid that is in direct contact with the measured liquid is used as a “reference” liquid, but e miscible with it, such as organosilicon having known coefficients of volumetric expansion and contraction.

The horizontal branch 15 of the measuring column is made with a variable diameter and has a section 16 of a calibrated (one diameter) pipe length L ₁ with a smaller diameter D ₁ and section 17 calibrated

pipeline with a sharp increase in diameter D ₂ and length L ₂ , where: L ₁ = (2 ÷ 3) D ₁ , and L ₂ = (3 ÷ 4) D ₂ , and taken from the source: A.D. Altshul, L.S. Zhivotovsky, L.P. Ivanov “Hydraulics and Aerodynamics”, M., Stroyizdat, 1985. The first pressure sensor 18 is located at section 17 and is located at a distance from it L = (2 ÷ 3) D ₂ at one level, the second pressure sensor 19. The pressure sensors 18 and 19 are connected by impulse tubes with a "reference" liquid 20 and 21, respectively, with the second pressure difference sensor 22. Section 17 ends with an outlet pipe.

Absolute pressure sensor 2, a “reference” liquid thermometer 7, a measured liquid thermometer 14, and two pressure difference sensors 13 and 22 are connected to a recording unit 23 (BOI - information processing unit), which calculates the density of the measured liquid and its flow rate using the program laid down in it and outputs to the visualization tool, for example, a computer (not shown in FIG.). In the place of contact of the reference fluid with the measured fluid, “mini” chambers for transmitting pressure are made (not shown in FIG.).

Density meter - a flowmeter of liquid media works as follows.

Liquid medium (measured liquid) “Q” comes from the inlet pipe (where the absolute pressure sensor 2 measures the pressure of the measured liquid and passes to block 23), and rises along it to the input of the ascending branch 3, while the lower pressure sampler (sensor) 4 transfers pressure to the negative chamber of the pressure difference sensor 13 through a pulse tube with a “reference” liquid 11, and the upper pressure sampler (sensor) 5 transfers pressure through a sleeve with a “reference” liquid 6 and pulse tubes 9 and 12 to the positive chamber of the pressure difference sensor 13 , by the readings of which are sent to block 23. Thermometer 8 measures the temperature of the "reference" liquid. At the exit of the vertical branch

the temperature of the measured liquid is measured by a temperature sensor 14, the readings of which are sent to block 23.

When liquid flows along a horizontal branch, the first pressure sensor 18 transmits readings to the negative chamber of the second pressure difference sensor 22, the second pressure sensor 19 transmits readings to the plus chamber of the pressure difference sensor 22, which is connected to the recording unit 23.

In the measurement process, a method is used to compare the static parameters of a “reference” fluid with the changing parameters of a fluid medium.

The essence of the measurement is disclosed in the following example of calculating the density of the measured liquid.

The measured flow "Q" from the inlet pipe, where the absolute pressure P is measured, enters the inlet of the vertical section of the pipeline and passes through it, while measuring the differential pressure of the liquid column at two points: the first (lower) pressure sensor and the second (upper) a pressure sensor, as well as the temperature of the measured liquid t _W and the temperature of the "reference" liquid t _et in the sleeve. The pressure drop on the ascending branch is determined by the following formula:

,

where: ΔР is the pressure difference between the column of the "reference" liquid and the sum of the pressures of the hydrostatic liquid column and the friction pressure loss in the ascending branch at a distance of N.

The pressure created by the "reference" fluid is determined by the formula:

,

where: ρ _tet is the density of the "reference" fluid, kg / m ³ ,

g is the acceleration of gravity, m / s ² ,

N is the distance between the points of pressure selection, m

ΔP _W - hydrostatic pressure of a liquid column equal to the distance H, is determined by the formula:

,

where: ρ _W - the density of the liquid, kg / m ³ .

Since the distance H between the pressure selection points is selected from the condition H = (1 ÷ 1.5) D, where D is the diameter of the pipeline of the ascending branch 3, friction losses can be neglected, since they are not significant and based on the calculated loss formula for friction:

,

where: λ is the coefficient of hydraulic resistance;

V is the fluid flow rate in the pipeline with a diameter of D, is limited by the Reynolds number: Re = 4 · 10 ⁴ , selected by calculation and experimental method.

The coefficient of hydraulic resistance λ can be reduced by choosing the smallest roughness of the vertical part of the pipe due to the inner coating made of an epoxy layer or using vitrification, etc.

Then formula (1) can be written as follows:

,

,

wherein: ρ _tet = ρ _20et [1-β _t (t _et -20) + K _p P], kg / m ³ .

where: ρ _{20 et} is the density of the "reference" fluid under normal conditions (t = 20 ° C; P = 0.10 ³ MPa).

β _t is the coefficient of volume expansion of the "reference" liquid when the temperature changes by 1 ° C;

t _et - measured temperature of the "reference" fluid, ° C;

To _p - the coefficient of volumetric compression of the "reference" fluid, 1 / MPa;

P is the absolute pressure, MPa.

The coefficients β _t and K _p are taken from the state standard data system.

The measurement of fluid flow is carried out taking into account the measured fluid density ρ _W and the measured pressure drop in the horizontal section 17 of the pipeline with a diameter of D ₂ taking into account the diameter of D ₁ .

The division difference ΔP ₁ on the horizontal section of the pipeline D _{2 is} carried out according to the formula (A.D. Altshul, L.S. Zhivotovsky, L.P. Ivanov "Hydraulics and aerodynamics", M., Stroyizdat, 1985:

where: ΔP ₁ - pressure drop, Pa;

V is the flow velocity in a calibrated pipeline with a diameter of D ₁ , m / s;

D ₁ - diameter of the calibrated pipeline m;

D ₂ - diameter of the calibrated pipeline m;

ρ _W - the density of the liquid, kg / m ³ ;

From formula (6) we find the flow rate V in a calibrated pipeline with a diameter of D ₁ .

Knowing the speed V, density ρ _W and diameter D ₁ , we determine the flow rate of the mass of liquid through a calibrated pipeline D ₁ according to the formula:

or

.

In the proposed product, the measurement accuracy is achieved both through the application of the method of comparing the static parameters of the "reference" fluid

with changing parameters of the working medium, and through the use of a calibrated pipeline with a sharp expansion of the diameter as a hydrodynamic type sensor, as well as minimizing friction pressure losses by applying the surface with the smallest roughness in the horizontal measuring section.

For the proposed product, laboratory tests on water were carried out, positive results were obtained confirming the correctness of the choice of a constructive solution for measuring the density and flow rate of a liquid.

Claims (3)

1. A densitometer-flowmeter of liquid media containing an inlet pipe, a measuring column made of vertical and horizontal branches, an outlet pipe, an absolute pressure sensor, a temperature sensor for the liquid medium, pressure taps mounted respectively on the vertical and horizontal branches, two pressure difference sensors, impulse tubes filled with a "reference" liquid, perceiving the pressure of a liquid medium directly by the contact method, a temperature sensor of the "reference" liquid and an additional pressure selector lines installed on a sleeve filled with a “reference” fluid and a recording unit, characterized in that the horizontal branch of the measuring column contains a section of a calibrated pipeline of length L _{1 of} smaller diameter D ₁ and a section of a calibrated pipeline of length L ₂ with a sharp expansion of its diameter D ₂ in the outlet the nozzle, and the ratio of the squares

, and the selection of lengths is carried out from the condition: L ₁ = (2 ÷ 3) D ₁ and L ₂ = (3 ÷ 4) D ₂ , and is equipped with a second pressure sampler located from the first pressure sampler at a distance L = (2 ÷ 3) D ₂ in the section with a diameter of D ₂ , while the first and second pressure sampling devices are connected by impulse tubes filled with a “standard” liquid with the first pressure difference sensor, and the vertical branch of the measuring column with a diameter D is made with an inner coating that reduces the resistance to movement of the fluid flow, and equipped with a second - upper pressure tester located from the first - lower pressure tester at a distance H = (1 ÷ 1.5) D, and the first - the lower pressure tester of the vertical branch and an additional pressure tester on the mentioned sleeve are located at the same level and are connected to the second pressure difference sensor by pulse tubes with a “reference” liquid, and the upper is the second pressure tester connected to the mentioned sleeve by impulse tubes with a "reference" liquid, and the density and flow rate of the liquid medium is determined respectively by the formulas:

,

, where ρ _W - the density of the liquid, kg / m ³ ; ρ _tet is the density of the "reference" fluid, reduced to operating conditions, kg / m ³ ; ΔР is the pressure difference between the column of the "reference" liquid and the sum of the hydrostatic pressure of the liquid medium and friction losses at the site of the height H of the pipeline, Pa; g is the acceleration of gravity, m / s; N is the distance between the upper and lower points of pressure selection, m; M is the mass flow rate of the liquid medium, kg / s; D ₁ and D ₂ - respectively, the diameters of the calibrated pipes of smaller and larger diameters, m; ΔP ₁ is the pressure drop measured over the length L _{2 of the} pipeline D ₂ , Pa. 2. The density meter-liquid flow meter according to claim 1, characterized in that the absolute pressure sensor of the liquid medium, the temperature sensor of the liquid medium, the temperature sensor of the "reference" liquid, as well as two pressure difference sensors are connected to the recording unit. 3. The densitometer-flowmeter of liquid media according to claim 1, characterized in that the inner coating of the vertical branch of the pipeline with a diameter of D, which reduces the resistance to movement of the fluid flow, can be performed, for example, by glazing or using an epoxy layer and other material.