RU2782508C1 - Using steam pressure to determine the concentration of components in a multicomponent fluid - Google Patents

Abstract

FIELD: measuring technology.

SUBSTANCE: system (700) is provided for using steam pressure to determine the concentration of a component in a multicomponent fluid. The system (700) includes an electronic device (710) connected with the possibility of communication with a measuring transducer (720) configured to perceive a multicomponent fluid medium. The electronic device (710) is configured to determine the first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multicomponent fluid, determine the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multicomponent fluid, and determine the multicomponent vapor pressure, the multicomponent vapor pressure is the vapor pressure of the multicomponent fluid. The electronic device (710) is also configured to determine the concentration of at least one of the first component and the second component based on the multicomponent vapor pressure, the first vapor pressure and the second vapor pressure. The electronic device (710) is additionally configured to determine the vapor pressure based on the gain of the exciting signal provided to the measuring transducer (720).

EFFECT: determination of the exact true value of the vapor pressure.

12 cl, 7 dwg

Description

The field of technology to which the invention relates

The embodiments described below relate to determining the concentration of a component in a multi-component fluid stream and, more specifically, to using vapor pressure to determine component concentrations in a multi-component fluid stream.

State of the art

Vibration sensors such as, for example, vibratory density meters and Coriolis flow meters are generally known and used to measure mass flow and other information for substances flowing through a tube in a flow meter. Exemplary Coriolis flowmeters are disclosed in US Pat. No. 4,109,524, US Pat. No. 4,491,025, and File 31,450, all to J. E. Smith et al. These flow meters have one or more tubes in a straight or curved configuration. The configuration of each tube in a Coriolis mass flowmeter, for example, has a plurality of free oscillation modes, which may be of a simple bend type, a torsion type, or a coupled type. Each tube can be oscillated in the preferred mode.

Material flows into the flowmeter from a connected pipeline on the inlet side of the flowmeter, is directed through the pipe(s), and exits the flowmeter through the outlet side of the flowmeter. The modes of free oscillation of a vibrating system are determined in part by the combined mass of the tubes and the material flowing in the tubes.

When there is no flow through the flowmeter, a driving force applied to the pipe(s) causes all points along the pipe(s) to oscillate with identical phase or a small "zero correction" which is the time delay measured at zero flow. When material begins to flow through the flowmeter, Coriolis forces force each point along the pipe(s) to have a different phase. For example, the phase at the inlet end of the flow meter lags the phase at the driver center position, while the phase at the outlet leads the phase at the driver center position. Load cells on the pipe(s) generate sinusoidal signals characteristic of the movement of the pipe(s). The signals output from the strain gauges are processed to determine the time delay between the strain gauges. The time delay between two or more strain gauges is proportional to the mass flow rate of the material flowing through the pipe(s).

The meter electronics coupled to the driver generates a drive signal to drive the driver and determine mass flow and other material properties from the signals received from the strain gauges. The driving device may comprise one of many well known configurations; however, the magnet and the back-to-back field coil have been successfully used in the flow meter industry. An alternating current is applied to an excitation coil to vibrate the pipe(s) at the desired amplitude and frequency of the flow pipe. It is also known in the art to provide strain gauges as a magnet and coil configuration very similar to the driver configuration. However, while the driver is receiving a current that induces movement, the strain gauges can use the motion provided by the driver to induce a voltage.

Vapor pressure is an important property in applications that deal with the flow and storage of volatile liquids such as gasoline, NGLs, and LPG. The vapor pressure provides an indication of how the volatile liquids may act during processing and further indicates the conditions under which bubbles are likely to form and pressure is likely to be generated. As such, the vapor pressure measurement of volatile liquids increases safety and prevents damage to transport tanks and infrastructure. For example, if the vapor pressure of the fluid is too high, voids may occur during pumping and transport operations. In addition, the vapor pressure of a tank or process line can potentially rise above safe levels due to temperature changes. Therefore, it is often required that the vapor pressure be known before storage and transport.

In many applications, it is also desirable to know the concentrations of the components in the multicomponent fluid. This may require additional equipment and/or laboratory samples. On-site measurement is more reliable as it eliminates the need for periodic sampling and completely eliminates the risk of changes in fluid properties between the time of sample collection and laboratory testing. In addition, safety is improved through the availability of real-time measurements, since unsafe conditions can be corrected immediately. Additionally, money is saved as regulatory enforcement can be carried out through on-site sample checks, and inspection and enforcement decisions can be made with little delay or interruption in the process. Accordingly, it is desirable to determine the concentrations of components in a multicomponent fluid using the vapor pressure of the fluid.

The essence of the invention

A system is provided for using vapor pressure to determine the concentration of a component in a multicomponent fluid. According to an embodiment, the system comprises an electronic device communicatively coupled to a transducer configured to detect a multicomponent fluid. The electronic instrument is configured to determine the first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multi-component fluid, determine the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multi-component fluid, determine the multi-component vapor pressure, the multi-component vapor pressure is vapor pressure multi-component fluid, and determine the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure and the second vapor pressure.

A method is provided for using vapor pressure to determine the concentration of a component in a multi-component fluid. According to an embodiment, the method comprises determining a first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multicomponent fluid, determining the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multicomponent fluid, using a transducer having the multicomponent fluid to determine the multi-component vapor pressure, the multi-component vapor pressure is the vapor pressure of the multi-component fluid, and determining the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure.

Aspects

According to an aspect, the system (700) for using vapor pressure to determine the concentration of a component in a multicomponent fluid comprises an electronic instrument (710) communicatively coupled to a transducer (720) configured to detect the multicomponent fluid. The electronic instrument (710) is configured to determine the first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multi-component fluid, determine the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multi-component fluid, determine the multi-component vapor pressure, the multi-component vapor pressure is the vapor pressure of the multi-component fluid, and determine the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure.

Preferably, the electronic instrument (710) configurable to determine the concentration of at least one of the first component and the second component based on the multicomponent vapor pressure, the first vapor pressure, and the second vapor pressure comprises an electronic instrument (710) configurable to use equations:

; и

; and

;

;

where:

P _m is the multi-component vapor pressure and is the sum of the pressures exerted by each component of the multi-component fluid, which is a two-component fluid;

,

являются, соответственно, первым давлением пара и вторым давлением пара, когда первый компонент и второй компонент являются беспримесными текучими средами; и

,

are respectively the first vapor pressure and the second vapor pressure when the first component and the second component are pure fluids; and

,

являются, соответственно, молярными долями первого и второго компонента в двухкомпонентной текучей среде.

,

are, respectively, the mole fractions of the first and second components in the two-component fluid.

Preferably, the electronic instrument (710) configurable to determine the concentration of at least one of the first component and the second component based on the multicomponent vapor pressure, the first vapor pressure, and the second vapor pressure comprises an electronic instrument (710) configurable to determine concentrations of the first component, the second component and the third component using the equations:

;

;

;

;

; и

; and

;

;

where:

является многокомпонентным давлением пара многокомпонентной текучей среды, где многокомпонентная текучая среда является трехкомпонентной текучей средой;

is a multi-component vapor pressure of a multi-component fluid, where the multi-component fluid is a three-component fluid;

и

являются соответствующими молярными долями первого компонента, второго компонента и третьего компонента трехкомпонентной текучей среды;

and

are the respective mole fractions of the first component, the second component, and the third component of the ternary fluid;

и

являются, соответственно, первым давлением пара, вторым давлением пара и третьим давлением пара, когда первый компонент, второй компонент и третий компонент являются беспримесными текучими средами;

and

are respectively the first vapor pressure, the second vapor pressure and the third vapor pressure when the first component, the second component and the third component are pure fluids;

является молекулярным весом трехкомпонентной текучей среды;

is the molecular weight of the ternary fluid;

,

и

являются соответствующими молекулярными весами первого компонента, второго компонента и третьего компонента;

,

and

are the respective molecular weights of the first component, the second component and the third component;

,

и

являются соответствующими массовыми долями первого компонента, второго компонента и третьего компонента в трехкомпонентной текучей среде и, соответственно равны

,

, и

;

,

and

are the respective mass fractions of the first component, the second component and the third component in the ternary fluid and are respectively equal to

,

, and

;

,

и

являются соответствующими плотностями первого компонента, второго компонента и третьего компонента трехкомпонентной текучей среды; и

,

and

are the respective densities of the first component, the second component, and the third component of the ternary fluid; and

является плотностью трехкомпонентной текучей среды.

is the density of the ternary fluid.

Preferably, the electronic instrument (710) is further configured to determine the density of the multicomponent fluid in the transmitter (720) based on the sensor signals provided by the transmitter (720).

Preferably, the electronic instrument (710) is further configured to determine the true vapor pressure of the multicomponent fluid based on the static pressure of the multicomponent fluid in the transducer (720).

Preferably, the electronic instrument (710) is further configured to determine the vapor pressure based on the gain of the drive signal provided to the transducer (720).

Preferably, the electronic device (710) is the measuring electronic device (20), and the measuring transducer (720) is the measuring unit (10) of the vibration meter (5).

According to an aspect, the method of using vapor pressure to determine the concentration of a component in a multicomponent fluid comprises determining a first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multicomponent fluid, determining the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multicomponent fluid, using a transducer having a multi-component fluid to determine the multi-component vapor pressure, the multi-component vapor pressure is the vapor pressure of the multi-component fluid, and determining the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and second steam pressure.

Preferably, determining the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure and the second vapor pressure comprises using the equations:

; и

; and

;

;

where:

P _m is the multi-component vapor pressure and is the sum of the pressures exerted by each component of the multi-component fluid, which is a two-component fluid;

,

являются, соответственно, первым давлением пара и вторым давлением пара, когда первый компонент и второй компонент являются беспримесными текучими средами; и

,

are respectively the first vapor pressure and the second vapor pressure when the first component and the second component are pure fluids; and

,

являются, соответственно, молярными долями первого и второго компонента в двухкомпонентной текучей среде.

,

are, respectively, the mole fractions of the first and second components in the two-component fluid.

Preferably, determining the concentration of at least one of the first component and the second component based on the multicomponent vapor pressure, the first vapor pressure, and the second vapor pressure comprises determining the concentrations of the first component, the second component, and the third component using the equations:

;

;

;

;

; и

; and

;

;

where:

является многокомпонентным давлением пара многокомпонентной текучей среды, где многокомпонентная текучая среда является трехкомпонентной текучей средой;

is a multi-component vapor pressure of a multi-component fluid, where the multi-component fluid is a three-component fluid;

и

являются соответствующими молярными долями первого компонента, второго компонента и третьего компонента трехкомпонентной текучей среды;

and

are the respective mole fractions of the first component, the second component, and the third component of the ternary fluid;

и

являются, соответственно, первым давлением пара, вторым давлением пара и третьим давлением пара, когда первый компонент, второй компонент и третий компонент являются беспримесными текучими средами;

and

are respectively the first vapor pressure, the second vapor pressure and the third vapor pressure when the first component, the second component and the third component are pure fluids;

является молекулярным весом трехкомпонентной текучей среды;

is the molecular weight of the ternary fluid;

,

и

являются соответствующими молекулярными весами первого компонента, второго компонента и третьего компонента;

,

and

are the respective molecular weights of the first component, the second component and the third component;

,

и

являются соответствующими массовыми долями первого компонента, второго компонента и третьего компонента в трехкомпонентной текучей среде и, соответственно, равны

,

и

;

,

and

are the respective mass fractions of the first component, the second component and the third component in the ternary fluid and are respectively equal to

,

and

;

,

и

являются соответствующими плотностями первого компонента, второго компонента и третьего компонента трехкомпонентной текучей среды; и

,

and

are the respective densities of the first component, the second component, and the third component of the ternary fluid; and

является плотностью трехкомпонентной текучей среды.

is the density of the ternary fluid.

Preferably, the method further comprises determining the density of the multicomponent fluid in the transmitter based on sensor signals provided by the transmitter.

Preferably, the method further comprises determining the true vapor pressure of the multicomponent fluid based on the static pressure of the multicomponent fluid in the transmitter.

Preferably, the method further comprises determining the vapor pressure based on the gain of the drive signal provided to the transmitter.

Preferably, the transducer is the measurement unit of a vibration meter.

Brief description of the drawings

The same reference number represents the same element throughout the drawings. It should be understood that the drawings are not necessarily drawn to scale.

Fig. 1 shows vibration meter 5.

Fig. 2 is a block diagram of the meter electronics 20 of the vibration meter 5.

Fig. 3 shows a graph 300 illustrating the relationship between the drive gain and the gas-liquid ratio that can be used to determine the vapor pressure using the coefficient of the vapor pressure meter.

Fig. 4 shows a graph 400 illustrating how the static pressure of a fluid in a vibrating meter can be used to determine vapor pressure.

Fig. 5 shows a system 500 for determining the vapor pressure of a fluid.

Fig. 6 shows a method 600 for using vapor pressure to determine the concentration of a component in a multi-component fluid.

Fig. 7 shows a system 700 for using vapor pressure to determine the concentration of a multicomponent fluid.

Detailed description of the invention

Fig. 1-7 and the following description depict specific examples to teach those skilled in the art how to create and use the best mode of steam pressure use cases for determining component concentrations in a multi-component fluid. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form several uses of vapor pressure to determine component concentrations in a multicomponent fluid. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

Fig. 1 shows a vibration meter 5. As shown in FIG. 1, the vibration meter 5 includes a meter assembly 10 and a meter electronics 20. The meter assembly 10 is responsive to the mass flow and density of the process material. The meter electronics 20 is connected to the meter assembly 10 via leads 100 to provide density, mass flow, temperature information via path 26 and/or other information.

Measuring assembly 10 includes a pair of nozzles 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel tubes 130 and 130', an excitation mechanism 180, a resistive temperature sensor (RTD) 190, and a pair of sensors- converters 170l and 170r. The tubes 130 and 130' have two substantially straight inlet legs 131, 131' and outlet legs 134, 134', which converge towards each other at tube-mounting blocks 120 and 120'. The tubes 130, 130' bend at two symmetrical locations along their length and are substantially parallel throughout their length. The spacer plates 140 and 140' serve to define the axis W and W' about which each tube 130, 130' oscillates. The branches 131, 131' and 134, 134' of the tubes 130, 130' are fixedly attached to the tube mounting blocks 120 and 120', and these blocks, in turn, are fixedly attached to the nozzles 150 and 150'. This provides a continuous closed path of the material through the measuring unit 10.

When flanges 103 and 103' having openings 102 and 102' are connected via inlet end 104 and outlet end 104' to a process line (not shown) that carries the process material that is being measured, the material enters the inlet end 104 of the meter through the orifice. 101 in the flange 103 and is led through the nozzle 150 to the tube inserter 120 having a surface 121. At the nozzle 150, the material is separated and guided through the tubes 130, 130'. Upon exiting the tubes 130, 130', the process material is recombined into one stream in the unit 120' of the installation having a surface 121' and the nozzle 150' and is then directed to the outlet end 104' connected by a flange 103' having holes 102' with a production line (not shown).

Tubes 130, 130' are selected and suitably mounted on tube mounting blocks 120, 120' so as to have substantially the same mass distribution, moments of inertia, and Young's modulus about bending axes W--W and W'--W', respectively. These bending axes extend through spacer plates 140, 140'. Because the Young's modulus of the tubes changes with temperature and this change affects the calculation of flow and density, RTD 190 is mounted on tube 130' to continuously measure the temperature of tube 130'. The temperature of tube 130', and hence the voltage generated at the ends of RTD 190 for a given current passing through it, is controlled by the temperature of the material passing through tube 130'. The temperature dependent voltage generated at the ends of the RTD 190 is used in a well known manner by the meter electronics 20 to compensate for a change in the elastic modulus of the tubes 130, 130' due to any changes in tube temperature. The RTD 190 is connected to the meter electronics 20 via terminal 195.

Both tubes 130, 130' are driven by the drive mechanism 180 in opposite directions about their respective bending axes W and W', and this is referred to as the first out-of-phase bending waveform of the flowmeter. This drive mechanism 180 may include any one of a variety of well known arrangements such as a magnet mounted on tube 130' and an inter-connected winding mounted on tube 130, through which an alternating current is passed to vibrate both tubes 130, 130'. A suitable drive signal is applied by meter electronics 20, via terminal 185, to drive mechanism 180.

The meter electronics 20 receives the RTD temperature signal at terminal 195, and the left and right sensor signals appearing at terminals 100 carrying the left and right sensor signals 165l, 165r, respectively. The meter electronics 20 generates a drive signal appearing at terminal 185 for the drive mechanism 180 and the vibrating tubes 130, 130'. node 10. This information, along with other information, is applied by the meter electronics 20 via path 26 as a signal.

The mass flow rate can be formed according to the equation:

[1]

[one]

The term Δt contains an operationally obtained (i.e. measured) time delay value containing the time delay that exists between the signals of the transducers, for example, when the time delay exists due to Coriolis effects associated with mass flow through the vibration meter 5. The measured term Δt, ultimately determines the mass flow rate of the fluid as it flows through vibratory meter 5. The Δt ₀ term contains a time delay with a zero flow calibration constant. The Δt ₀ term is typically determined at the factory and programmed into the vibration meter 5. The time delay at the zero flow term Δt ₀ will not change even when the flow conditions change. The flow calibration factor FCF is proportional to the stiffness of the vibration meter 5.

Fluid Pressures in a Vibrating Meter

, равна скорости, с которой она выходит на выпуске (

). Этот принцип, что массовый расход

на впуске должен быть равен массовому расходу (

) на выпуске, иллюстрируется посредством уравнения [2] ниже. Перемещаясь от впуска к выпуску, массовый расход сохраняется в каждой точке вдоль трубы. Однако может быть уменьшение в проходном сечении на полпути между впуском и выпуском. Это уменьшение в проходном сечении требует, чтобы скорость текучей среды возросла (v↑), чтобы поддерживать одинаковый массовый расход и соблюдать сохранение принципов массы.Assume an incompressible fluid under stable conditions, the rate at which the mass enters a control volume (such as a pipe) at the inlet

, is equal to the speed with which it exits at the outlet (

). This principle that mass flow

at the inlet must be equal to the mass flow (

) at the outlet is illustrated by Equation [2] below. Moving from inlet to outlet, mass flow is maintained at every point along the pipe. However, there may be a reduction in the flow area halfway between inlet and outlet. This reduction in flow area requires that the fluid velocity be increased (v↑) to maintain the same mass flow rate and respect the conservation of mass principles.

; [2]

; [2]

where:

является массовым расходом текучей среды;

is the mass flow rate of the fluid;

является средней скоростью текучей среды;

is the average fluid velocity;

является плотностью текучей среды;

is the fluid density;

является суммарной площадью поперечного сечения;

is the total cross-sectional area;

subscript 1 indicates inlet;

subscript 3 indicates release; and

subscript 2 indicates the middle of the path between intake and exhaust.

Additionally, the total pressure in the flow system is equal to the sum of the dynamic pressure and the static pressure:

[3]

[3]

может быть определено как:dynamic pressure

can be defined as:

; [4]

; [four]

и

определены выше относительно уравнения [2].where members

and

defined above with respect to equation [2].

Assume a steady, incompressible, inviscid, irrotational flow, Bernoulli's equation gives:

; [5]

; [5]

Where P refers to static stress and the term ρgz takes into account hydrostatic head due to lift changes. More specifically, g is the gravitational constant and z is the height. The viscous fragment of the pressure drop can be treated with a separate loss term in the Bernoulli equation.

; [6]

; [6]

where:

является коэффициентом трения;

is the coefficient of friction;

является длиной трубы; и

is the length of the pipe; and

является диаметром трубы.

is the pipe diameter.

The lower equation [7] is a version of the Bernoulli equation that takes into account the frictional losses associated with movement through the pipe. As fluid moves through the pipe, the fluid dissipates energy and pressure drops between the ends of that section of pipe. This loss in pressure is irrecoverable since the energy from the fluid has been wasted through frictional losses. Accordingly, the following equation can account for this loss:

[7]

[7]

This relationship can be applied to the exemplary pipe described above with reference to Equation [2]. As fluid moves from inlet to midway between inlet and outlet, there is a change in velocity to maintain mass flow. Therefore, in maintaining the ratio shown in equation [7], the dynamic pressure increases, causing the static pressure to decrease. When the fluid moves to the outlet from the middle of the path between the inlet and outlet, the static pressure is restored according to the same principles. That is, moving towards the outlet from the middle of the path between the inlet and outlet, the flow area increases; therefore, the fluid velocity decreases, causing the dynamic pressure to decrease while restoring some of the original static pressure. However, the static outlet pressure will be lower due to non-recoverable friction losses.

This may cause the inlet and outlet static pressures to be greater than the vapor pressure of the fluid, while the static pressure between the inlet and outlet is less than the vapor pressure of the fluid. As a result, although the static pressures at the inlet and outlet are both greater than the vapor pressure of the fluid, flashing or outgassing may still occur in the tube. Additionally, a vibratory meter, such as a Coriolis flow meter, may be inserted into a conduit that has a diameter that is different from the diameter of the tube or tubes in the vibratory meter. As a result, when outgassing is detected in the vibrator, the pressure measured in the pipeline may not be the vapor pressure of the fluid in the vibrator.

Measuring electronic device - excitation gain

Fig. 2 is a block diagram of the meter electronics 20 of the vibration meter 5. In operation, the vibration meter 5 provides various measurement values that can be output, including one or more of measured or averaged mass flow, volume flow, individual flow component mass, and volume flow, and the total flow, including, for example, the volume and mass flow of the individual components of the flow.

Vibration meter 5 generates a response vibration. The response vibration is received and processed by the meter electronics 20 to generate one or more fluid measurement values. Values may be observed, recorded, stored, summed and/or output. The meter electronics 20 includes an interface 201, a processing system 203 in communication with the interface 201, and a storage system 204 in communication with the processing system 203. While these components are shown as separate units, it should be understood that meter electronics 20 may be comprised of various combinations of combined and/or separate components.

Interface 201 is configured to communicate with measurement node 10 of vibration meter 5. Interface 201 can be configured to connect to leads 100 (see FIG. 1) and communicate with driver 180, sensors 170l and 170r, and multiple RTDs 190 , for example. The interface 201 can be further configured to communicate over the communication channel 26 with, for example, external devices.

Processing system 203 may include any kind of processing system. The processing system 203 is configured to retrieve and execute stored programs in order to control the vibration meter 5. The storage system 204 can store programs including a flowmeter program 205, a valve control program 211, a drive gain program 213, and a steam pressure program 215. The storage system 204 may store measurements, received values, operating values, and other information. In some embodiments, the storage system stores mass flow (m) 221, density (ρ) 225, density threshold 226, viscosity (μ) 223, temperature (T) 224, pressure 209, drive gain 306, gain threshold 302 excitation, gas entrainment threshold 244, gas entrainment fraction 248, and any other variables known in the art. Programs 205, 211, 213, 215 may contain any marked signal, and other variables that are known in the art. Other measurement/processing programs are considered and are within the scope of the description and claims.

As can be appreciated, more or fewer values may be stored in the storage system 204. For example, vapor pressure can be determined without using the viscosity 223. For example, estimates of viscosity based on pressure drop or a friction function as a function of flow. However, the viscosity 223 can be used to calculate the Reynolds number, which can then be used to determine the coefficient of friction. The Reynolds number and coefficient of friction can be used to determine the viscous pressure drop in a tube, such as the tubes 130, 130' described above with reference to FIG. 1. As may be appreciated, the Reynolds number may optionally be used.

The flow meter program 205 can produce and store fluid quantities and flow measurements. These values may contain substantially instantaneous measurement values, or may contain summed or accumulated values. For example, the flow meter program 205 may generate mass flow measurements and store them in mass flow storage 221 of storage system 204, for example. The flow meter program 205 may generate density measurements 225 and store them in density storage 225, for example. Mass flow 221 and density 225 are determined from the response vibration as previously discussed and as known in the art. Mass flow and other measurements may contain a substantially instantaneous value, may contain a sample, may contain an average value over a time interval, or may contain an accumulated value over a time interval. The time interval may be selected to correspond to a block of time during which certain fluid states are detected, such as a liquid fluid state only, or alternatively, a fluid state including liquids and entrained gas. In addition, other mass and volume flow rates and associated quantities are considered to be within the scope of the description and claims.

Drive gain threshold 302 can be used to distinguish between periods of flow, no flow, mono/two phase boundary (when a fluid phase transition occurs) and entrained gas/mixed phase flow. Likewise, the density threshold 226 applied to the density index 225 can also be used, alone or in conjunction with drive gain, to distinguish gas/mixed phase entrainment flow. The drive gain factor 306 can be used as a measure of the vibration sensitivity of the vibrator tube 5 to the presence of fluids of different densities such as liquid and gaseous phases, for example, without limitation.

As used herein, the term "drive gain" refers to a measurement of the amount of power required to drive the flow tubes to a specific amplitude, although any suitable definition may be used. For example, the term "drive gain" may, in some embodiments, refer to drive current, sensor voltage, or any measured or received signal that indicates the amount of power required to drive flow tubes 130, 130' at a particular amplitude. Power gain can be used to detect multi-phase flow by using drive gain characteristics such as, for example, noise levels, signal standard deviation, measurement attenuation, and any other means known in the art to detect mixed phase flow. These readings can be compared between sensors 170l and 170r to detect mixed phase flow.

Fluid Phase Change Detection

Fig. 3 shows a graph 300 illustrating the relationship between the drive gain and the gas-liquid ratio that can be used to determine the vapor pressure using the coefficient of the vapor pressure meter. As shown in FIG. 3, plot 300 includes an average void fraction axis 310 and a drive gain axis 320. The average void fraction axis 310 and the drive gain axis 320 are incremented as a percentage, although any suitable units and/or ratios may be used.

Plot 300 includes curves 330 that are relationships between drive gains and gas-liquid ratios for various flow rates. As shown, the gas-liquid ratio is the average void fraction for curves 330, although any suitable gas-liquid ratio, such as gas volume fraction ("GVF") or gas entrainment fraction, may be used, and may be based on volume, cross-sectional area, or etc. As can be appreciated, the curves 330 are similar despite being associated with different costs. Also shown is a threshold drive gain line 340 that intersects curves 330 at approximately 0.20 percent average void fraction, which may be an average void fraction 330a that corresponds to a 40% drive gain. Also shown is the true vapor pressure excitation gain 332, which is approximately 10%. The true vapor pressure excitation gain 332 corresponds to a fluid in the measurement assembly that has a static pressure at which the fluid phase transition occurs and has a gas-liquid ratio of zero.

As can be seen, the plots 330 vary from a drive gain of about 10% to a drive gain of about 100% over a range of average void fractions from 0.00% to about 0.60%. As can be taken into account, a relatively small change in the average void fraction results in a significant change in the drive gain. This relatively small change can ensure that the occurrence of vaporization can be accurately detected by the drive gain.

Although a drive gain of 40% is shown corresponding to an average void fraction of 0.20%, the correspondence may be specific to the process. For example, a drive gain of 40% may correspond to other average void fractions in other operating fluids and conditions. Different fluids may have different vapor pressures and hence the occurrence of vaporization for fluids may occur at different flow rates. That is, a relatively low vapor pressure fluid will vaporize at higher rates, and a relatively high vapor pressure fluid may vaporize at lower rates.

As may also be taken into account, the threshold drive gain line 340 may be at alternative/other drive gains. However, it may be useful to have a drive gain of 40% to eliminate false detections of entrainment/mixed phase flow while also ensuring that the occurrence of vaporization is correctly detected.

Also, plots 330 use a drive gain, but other signals may be used, such as measured density, or the like. The measured density may increase or decrease due to the presence of voids in the fluid. For example, the measured density can, oddly enough, increase due to voids in relatively high frequency vibratory meters due to the effect of the speed of sound. In relatively low frequency meters, the measured density may decrease due to the fact that the void density is less compared to the fluid. These and other signals can be used alone or in combination to detect the presence of steam in the meter assembly.

As discussed above, the 0.20 percent average void fraction may be a reference average void fraction 330a that corresponds to a 40 percent drive gain value, which may be where the threshold drive gain line 340 intersects with the drive gain axis 320 . Accordingly, when the measured drive gain is 40% for the fluid in the measurement assembly, such as the measurement assembly 10 described above, then the average fluid void fraction may be about 0.20%. A void fraction of about 0.20% may correspond to fluid pressure due to the gas present in the fluid. For example, a void fraction of about 0.20% may correspond, for example, to a static pressure value.

Due to a certain relationship between the drive gain, or other signal such as density, and the reference average void fraction 330a, which may be the reference gas-liquid ratio, the vapor pressure value may be associated with the vapor pressure meter coefficient. For example, the meter assembly may vibrate as the static pressure rises or falls until a fluid phase change is detected. The vapor pressure value can then be determined from the static pressure, as will be described in more detail in the following with reference to FIG. 4. The determined vapor pressure value may correspond to, for example, the static pressure on threshold drive gain line 340. This determined vapor pressure value can be adjusted by the vapor pressure meter gain to match the true vapor pressure excitation gain 332 that exists where a phase transition occurs or a mono/two phase boundary is encountered. Accordingly, although the presence of gas in a fluid can be detected at a static pressure that differs from the true vapor pressure of the fluid, the true vapor pressure can still be determined.

Using the reference average void fraction 330a as an example, the static pressure in the sensing assembly may decrease until the drive gain reaches 40%, thereby indicating that the fluid in the sensing assembly has an average void fraction of 0.20%. The treatment system, such as the treatment system 203 described above, may determine that the fluid has begun to vaporize at static pressure, i.e., for example, proportionally higher than the static pressure corresponding to a 40 percent drive gain. For example, the true vapor pressure may be associated with a drive gain of approximately 10%. As can be appreciated, due to the uncertainties implied in the static pressure calculation (e.g., errors from the pressure transducer, flow measurement errors, etc.), the true vapor pressure may be proportionally lower than the calculated static pressure that is associated with 40% drive gain. The true vapor pressure corresponds to the static pressure of the fluid when the fluid phase transition occurs, but the gas-liquid ratio is zero.

Thus, the measured drive gain can be used to detect the gas, and can also result in a very accurate true vapor pressure. More specifically, the instant gassing first occurs, with a few very small bubbles present, the drive gain may not increase beyond the threshold drive gain line 340 for detection. The dynamic pressure may be increased, for example, by a pump that continues to increase the flow until the static pressure drops so that the drive gain crosses the threshold drive gain line 340. Depending on the application, this calculated static pressure (eg, uncorrected vapor pressure) can be corrected (eg, adjusted - reduced or increased) by a vapor pressure meter factor of, for example, ¹ psi to account for the delay in detection phase transition of the fluid. Those. The vapor pressure gauge factor can be determined and applied to the uncorrected vapor pressure reading as a function of drive gain to account for the difference in drive gain at which gas is detected and the true vapor pressure so as to detect very small volumes of gas.

Referring to FIG. 3, by way of example, a measured drive gain of 40% may correspond to the static pressure of the fluid in the meter assembly, i.e., for example, ¹ psi less than the static pressure corresponding to the drive gain associated with true pressure. pair. Accordingly, vibration meter 5 or meter electronics 20, or any suitable electronic device, may determine that the vapor pressure meter gain is ¹ psi and add this value to the static pressure associated with a 40 percent drive gain. As a result, the vibration meter 5 can accurately detect the phase change of the fluid, and therefore also accurately determine the vapor pressure of the fluid with the drive gain.

However, another phase transition detection means can be used that does not use the drive gain. For example, a phase transition can be detected through acoustic measurements, X-ray measurements, optical measurements, and so on. Also, combinations of the above implementations may be considered. For example, a bypass line that runs vertically in a loop with acoustic and/or optical measurements distributed vertically to determine where gas is first released. This height will then provide the necessary input to calculate the vapor pressure of the fluid in the vibration meter 5, as explained in the following.

Pressure drop in vibrating meter

Fig. 4 shows a graph 400 illustrating how the static pressure of a fluid in a vibrating meter can be used to determine vapor pressure. As shown in FIG. 4, graph 400 includes a position axis 410 and a static pressure axis 420. Position axis 410 is not shown in any particular length unit, but may be in units of inches, although any suitable unit of measure may be used. The static pressure axis 420 exists in units ^of pounds per square inch (psi), although any suitable unit of measurement may be used. Position axis 410 ranges from inlet ("IN") to outlet ("OUT") of the vibration meter.

Accordingly, the position from IN to OUT may correspond to the fluid, for example, in the measuring unit 10 shown in FIG. 1. In this example, the region from IN to approximately A may correspond to a fragment of the measuring node 10 between the flange 103 to the block 120 tube installation. A region from approximately A to approximately G may correspond to the tubes 130, 130' between the mounting blocks 120, 120'. The area from G to OUT may correspond to a fragment of the measuring unit 10 from the mounting block 120' to the flange 103'. Accordingly, the fluid in the meter assembly 10 (eg, at a position ranging from IN to OUT) may not include the fluid, eg, in the conduit into which the meter assembly 10 is inserted. The fluid in the meter assembly 10 may be the fluid in the tubes 130, 130'.

The plot 400 also includes a zero dynamic pressure plot 430 and a dynamic pressure change plot 440. The zero dynamic pressure plot 430 shows no change in dynamic pressure - the pressure is expected to decrease linearly from the inlet to the outlet of the vibration meter. The dynamic pressure graph 440 may represent the actual pressure in the vibrator inserted into the pipeline, with the diameter of the vibrator tube or tubes being smaller than the diameter of the pipeline. An exemplary vibration meter 5 is shown in FIG. 1, although any suitable vibration meter may be used. Accordingly, the fluid in a measurement assembly, such as the measurement assembly 10 described above, may have a reduced static pressure due to an increase in dynamic pressure. Also shown is a vapor pressure line 450 representing the vapor pressure of the fluid in the vibration meter.

The dynamic pressure graph 440 includes a static pressure drop portion 440a, a friction loss portion 440b, and a static pressure increase portion 440c. The dynamic pressure graph 440 also includes the minimum static pressure 440d. The static pressure drop section 440a may be due to an increase in fluid velocity causing an increase in dynamic pressure for that section of the vibrator. Friction loss portion 440b may correspond to a portion of a constant diameter tube or tubes in a vibration meter. Accordingly, friction loss portion 440b may not reflect an increase in fluid velocity and therefore may not reflect an increase in dynamic pressure. The static pressure increase section 440c may be due to a decrease in the fluid velocity, and therefore the decrease in static pressure during the static pressure drop section 440a can be restored. The static pressure drop portion 440a and the static pressure increase portion 440c may be static pressure changes at the meter assembly.

The portion of the dynamic pressure graph 440 below the vapor pressure line 450 that includes the minimum static pressure 440d may correspond to positions (e.g., approximately from position E to slightly after position G) where a fluid phase transition occurs in the fluid at measuring node, such as the measuring node 10 described above. As can be seen in FIG. 4, the minimum static pressure 440d is below the vapor pressure line 450. This indicates that the dynamic pressure graph 440 can be shifted upward by increasing the static pressure of the fluid in the measurement assembly. However, if the static pressure were to be increased by approximately ⁵ psig in order to shift the dynamic pressure curve 440 upward until the minimum static pressure 440d lies on the vapor pressure line 450, a fluid phase change could occur. be discovered. As the static pressure increases, the gas or vapor in the fluid in the meter assembly may become liquid. Conversely, if the dynamic pressure curve 440 is above the vapor pressure line 450 and the static fluid pressure in the meter assembly decreases until the minimum static pressure 440d lies on the vapor pressure line, then a fluid phase transition may be forming gas or vapor in a fluid medium.

As can be seen in FIG. 4, friction loss portion 440b decreases from a static pressure of about 68 lb/in ² at position A to a static pressure of about 55 lb/in ² at position G. As can be taken into account, a static pressure of about 55 lb/in ² at position G is less than steam pressure line 450, which is about 58 psi ^. As a result, even if the inlet and outlet static pressures are greater than the vapor pressure line 450, the fluid in the vibrating meter may still flash or outgas.

Accordingly, the static pressure at the inlet and outlet does not directly correspond to the vapor pressure of the fluid. In other words, the vapor pressure of the fluid may not be directly determined from the static pressure of the fluid in the conduit or external to the sensing assembly. The static pressure in the measuring assembly 10, or more specifically in the tubes 130, 130', can be accurately determined, for example, by measuring the inlet and outlet pressures and entering the dimensions of the vibration meter 5 (for example, the diameter and length of the tube 130, 130' ). However, in order to accurately determine the vapor pressure, a phase change in the fluid in the vibrator 5 may need to be induced, which can be caused by changing the static pressure of the fluid in the vibrator 5.

Fluid static pressure change

Fig. 5 shows a system 500 for determining the vapor pressure of a fluid. As shown in FIG. 5, system 500 is a bypass that includes a bypass inlet and a bypass outlet that connect to conduit 501. System 500 includes a pump 510 in fluid communication with an outlet of vibratory meter 5, illustrated as a Coriolis flowmeter, and a bypass outlet. The inlet pressure sensor 520 is in fluid communication with the inlet of the vibration meter 5 and the bypass inlet. An outlet pressure sensor 530 is placed between the outlet of the vibrator 5 and pump 510 and is configured to measure the static pressure of the fluid at the outlet of the vibrator 5. A flow control device 540, which is shown as a valve, is placed between the bypass inlet and the inlet pressure sensor 520.

Pump 510 may be any suitable pump that may, for example, increase the velocity of the fluid in vibrator 5. Pump 510 may, for example, include a variable frequency drive. The variable frequency drive may allow the pump 510 to control the fluid velocity of the fluid in the system 500. For example, the variable frequency drive may increase the fluid velocity of the fluid through vibrator 5, although the fluid velocity may be increased by any suitable pump. By increasing the speed of the fluid, the pump 510 can increase the dynamic pressure of the fluid in the vibrator 5, increasing the speed of the fluid.

Accordingly, the static pressure of the fluid in the vibrating meter 5 can be reduced. As an illustration, with reference to FIG. 4, the pump 510 may cause the dynamic pressure curve 440 to move down. Accordingly, although not shown in FIG. 4, if the dynamic pressure curve 440 is to be above the vapor pressure line 450, the pump 510 may induce flashing or outgassing, causing the dynamic pressure curve 440 to move downward. Similarly, by shifting the dynamic pressure curve 440 up to or above the vapor pressure line 450, the gas or vapor in the fluid may become a liquid.

Inlet pressure sensor 520 and outlet pressure sensor 530 may be any suitable pressure sensor configured to measure any fluid pressure. For example, inlet pressure sensor 520 and outlet pressure sensor 530 may measure the static pressure of the fluid in system 500. Additionally, or alternatively, inlet pressure sensor 520 and outlet pressure sensor 530 may measure the total fluid pressure in system 500. In one example, the dynamic fluid pressure can be determined by taking the difference between the total pressure and the static pressure of the fluid in the system 500 according to equation [3] above. For example, inlet pressure sensor 520 may measure the total pressure and static pressure of the fluid adjacent to, or at, the inlet of vibrator 5. Inlet pressure sensor 520 and/or meter electronics 20 in vibrator 5 may detect dynamic inlet pressure of vibrator 5. meter 5.

The flow control device 540 may increase the fluid velocity of the fluid in the system 500 when the position of the flow control device 540 moves from a partially closed position to a fully open position. For example, by reducing the flow restriction of the system 500 at the inlet of the vibratory meter 5, the fluid velocity can be increased in accordance with equation [2] above. This may shift the dynamic pressure curve 440 down so as to induce flashing or outgassing. Conversely, the flow control device 540 may decrease the fluid velocity of the fluid in the system 500, thereby shifting the dynamic pressure curve 440 upward and thereby causing the gas or vapor to condense.

When the flow control device 540 is opened, the fluid velocity will increase, but thus there will be static pressure at the inlet of the vibrating meter 5, and vice versa. The combination of flow control device 540 with pump 510 can provide a preferred process condition by partially closing flow control device 540 (eg, to restrict flow and reduce pressure downstream of flow control device 540) and increasing pump speed (eg, increasing flow) to to obtain desirable lower static pressure and higher speed.

While the static pressure of the fluid in the vibrator 5, or more specifically the meter assembly 10 in the vibrator 5, can be changed by pump 510 or flow control device 540, or a combination of both as described above, another means of changing the static pressure can be used. For example, the height z of the vibration meter 5 may vary. In order to reduce the static pressure of the fluid in the vibration meter 5, the height z can be increased. In order to increase the static pressure of the fluid in the vibration meter 5, the height z can be reduced. The height z of the vibrator 5 can be changed by any suitable means, such as a motorized hoist between the vibrator 5 and conduit 501 and a bellows between the vibrator 5, such as a flow control device 540 and a pump 510. Other means may be used, as well as a combination of different means (eg, a pump 510, a flow control device 540, and/or a motorized lift).

For example, if the flow through the bypass is sufficient, the pump may not necessarily be used. Only the flow control device 540 can be used. The flow control device 540 may be installed in other locations, such as downstream of the vibration meter 5. Alternatively, the flow control device 540 may not be used, for example, when a pump 510 and/or a motorized lift is used. In another alternative example, the meter may be installed in the main line instead of the bypass. Additionally, or alternatively, only a single pressure sensor may be used. For example, only the outlet pressure sensor 530 may be used. Inlet and/or outlet pressure sensors 520, 530 may be located in alternative locations. The outlet pressure sensor 530 and its location can be useful because the static pressure at the outlet pressure sensor 530 location can substantially stabilize relative to the fluid velocity after the fluid in the sensing assembly 10 is at vapor pressure. Those. any additional increase in fluid velocity may not cause a significant decrease in the static pressure measured by outlet pressure sensor 530.

Additional information can be derived from vapor pressure measurements. For example, if the flowing liquid is a mixture of two or more pure substances, vapor pressure can be used to estimate the concentrations of the liquid phase of the pure components (ie, volume or mass fractions of components) using Dalton's and Raoult's laws. Correlations for standard hydrocarbons or other fluids can be placed in the transmitter and added as a feature, similar to current concentration measurement curves. Additionally, the concentration of salt or other non-volatile solutions can be determined. These ideas are explained in the following:

Dalton's law of additional pressures, as expressed in equation [8], states that the total pressure exerted by a mixture of gases, P _m , is equal to the sum of the pressures exerted by each component of the mixture, P _i , if each component exists separately at the same temperature and volume , which is the mixture.

[8]

[eight]

At the low pressures exerted in the system 500 shown in FIG. 5, the behavior of gases can be assumed to approximate ideal gas behavior when Dalton's law best predicts the behavior of gas mixtures.

Raoult's law, which is expressed in equation [9], states that the partial pressure of each component, P _i , of an ideal mixture of liquids is equal to the vapor pressure of the pure component, P _i ^* , multiplied by its mole fraction in the liquid mixture or two-component fluid, x _i .

[9]

[9]

Using the equations described above and the vapor pressure lookup tables for the pure components of the liquid concentration for an ideal binary or two-component fluid, the following can be obtained:

, [10]

, [ten]

where:

P _m is the sum of the pressures exerted by each component of the mixture and may be equal to the vapor pressure of a multi-component fluid, such as a binary or two-component fluid; and

,

являются соответствующими частичными давлениями первого и второго компонента в двухкомпонентной текучей среде.

,

are the respective partial pressures of the first and second components in the two-component fluid.

равна целому минус вторая молярная доля

:

. Последующий пример иллюстрирует использование измеренного давления пара для определения концентраций жидкостей бинарной смеси.As can be taken into account, due to the fact that the multi-component fluid is a binary or two-component fluid, the first mole fraction

is equal to the whole minus the second mole fraction

:

. The following example illustrates the use of measured vapor pressure to determine the liquid concentrations of a binary mixture.

A liquid mixture of benzene (B) and toluene (T) flows through the process line at 95°C. A portion of the liquid flows through a bypass line where the vapor pressure will be determined using a system such as the system proposed in this specification. The static pressure in the bypass system drops until the Coriolis flow meter detects the formation of gas bubbles. The measured vapor pressure at this point is 101.32 kPa. The following illustrates how to determine the liquid concentration of each component.

. Следующим этапом является использование законов Дальтона и Рауля, чтобы связывать измеренное давление пара с концентрациями жидкостей:The first step may be to find the vapor pressure of pure components at 95°C. This information can be found in the literature:

. The next step is to use Dalton's and Raoult's laws to relate the measured vapor pressure to liquid concentrations:

.

.

. Так как

, следует, что

.With a simple simple root lookup block, the mole fraction for benzene can be solved for:

. Because

, follows that

.

Using Density

Density measurement and vapor pressure measurement can be combined to result in more equations and therefore be able to solve more unknown components. Typically, if the base densities of the pure formulations are known as a function of temperature, then the concentration software can accurately determine the volume fraction of up to two components. However, with the addition of the vapor pressure information described above, the three components can be differentiated, with component volume or mass fractions provided for each.

Providing the ability to determine the liquid fraction of three-component mixtures can increase the usable range of the concentration measurement or the net oil recovery computer. The additional equations needed for the three components are defined below, where φ refers to the volume fraction of each component and ρ is the density of each component, along with the measured density.

[11]

[eleven]

[12]

[12]

As an example, the following equation shows how the above laws of Dalton and Raoult can be used to determine the concentration of at least one component in a multi-component fluid, the multi-component fluid is a three-component fluid.

; [13]

; [13]

where:

является давлением пара трехкомпонентной текучей среды, которое может быть измерено посредством измерительного преобразователя;

is the vapor pressure of the three-component fluid, which can be measured by means of a transducer;

и

являются молярными долями трех компонентов трехкомпонентной текучей среды; и

and

are the mole fractions of the three components of the ternary fluid; and

и

являются давлениями пара каждого из компонентов в качестве беспримесной текучей среды; которые могут быть известны, например, из таблицы поиска.

and

are the vapor pressures of each of the components as a pure fluid; which may be known, for example, from a lookup table.

могут обязательно в сумме давать единицу:Mole fractions of the three components

may necessarily add up to one:

. [14]

. [fourteen]

, соответственно умноженные на их молекулярный вес, должны давать в сумме молекулярный вес трехкомпонентной текучей среды:In addition, the mole fractions of the three components

respectively multiplied by their molecular weight should sum to the molecular weight of the ternary fluid:

; [15]

; [fifteen]

where:

является молекулярным весом трехкомпонентной текучей среды; и

is the molecular weight of the ternary fluid; and

,

и

являются молекулярными весами каждого из компонентов в трехкомпонентной текучей среде.

,

and

are the molecular weights of each of the components in the ternary fluid.

Additionally, the reciprocal of the density of the ternary fluid may be equal to the sum of the mass fraction and density ratios of each of the components in the ternary fluid:

; [16]

; [16]

where:

,

, и

являются соответствующими массовыми долями первого, второго и третьего компонента в трехкомпонентной текучей среде и соответственно равны

,

, и

;

,

, and

are the corresponding mass fractions of the first, second and third component in a three-component fluid and are respectively equal to

,

, and

;

,

,

являются, соответственно, плотностями первого, второго и третьего компонента трехкомпонентной текучей среды; и

,

,

are, respectively, the densities of the first, second and third component of the three-component fluid; and

является плотностью трехкомпонентной текучей среды, которая может быть равна измеренной плотности

.

is the density of the ternary fluid, which may be equal to the measured density

.

As can be taken into account, there are seven equations and seven unknowns, and hence the concentrations of each component can be determined.

Even in mixtures with only two components, the measurement of the vapor pressure of a binary mixture can be used by itself to calculate the fractions of the mixture components; this will be especially useful in cases where the densities of the pure components are equal but their vapor pressures are different. Alternatively, the vapor pressure of the binary mixture can be used to provide a secondary check for density based algorithms even when the densities of the pure components differ.

Use of steam pressure

Fig. 6 shows a method 600 for using vapor pressure to determine the concentration of a component in a multi-component fluid. As shown in FIG. 6, at step 610, method 600 determines the first vapor pressure. The first vapor pressure is the vapor pressure of the first component of the multicomponent fluid. At 620, the method determines the second vapor pressure. The second vapor pressure is the vapor pressure of the second component of the multicomponent fluid. At 630, the method determines the multicomponent vapor pressure. Multi-component vapor pressure is the vapor pressure of a multi-component fluid. The multi-component vapor pressure of the multi-component fluid may be the sum of the pressures exerted by each component in the multi-component fluid. The method 600, at 640, determines the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure.

. Для трехкомпонентной текучей среды способ 600 может определять концентрацию первого компонента, второго компонента и/или третьего компонента с помощью уравнений [13]-[16], указанных выше.At 640, method 600 may include concentration of the first or second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure using the above equation [10], as well as the molar fraction ratios

. For a ternary fluid, the method 600 may determine the concentration of the first component, the second component, and/or the third component using the equations [13]-[16] above.

Method 600 may also include additional steps. For example, method 600 may determine the density of a multicomponent fluid in a transmitter based on sensor signals provided by the transmitter. For example, the density may be determined by measuring a frequency, such as a resonant frequency, of a transducer and using a correlation between the frequency and the density value to determine the density of the multicomponent fluid. The method 600 may also further determine the true vapor pressure of the multicomponent fluid based on the static pressure of the multicomponent fluid in the transmitter. The vapor pressure may be determined based on the drive signal gain provided to the transmitter. The transducer may be the measurement unit of a vibration meter, although any suitable transducer may be used, as explained in the following.

Fig. 7 shows a system 700 for using vapor pressure to determine the concentration of a multicomponent fluid. As shown in FIG. 7, system 700 consists of an electronic instrument 710 and a transducer 720. The electronic instrument 710 may be configured to determine the vapor pressure of a multicomponent fluid. For example, the electronic instrument 710 may be configured to determine the first and second vapor pressures, the first and second vapor pressures being the vapor pressures for the first component and second component of the multicomponent fluid, respectively. The electronic instrument 710 may also be configured to determine the multi-component vapor pressure when the multi-component vapor pressure is the vapor pressure of the multi-component fluid. The electronic instrument 710 may use vapor pressures to determine the concentration of the multicomponent fluid. For example, the electronic instrument 710 may be used to determine the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure.

The electronic instrument 710 may also be configured to determine the density of a multicomponent fluid. The density of a multi-component fluid may be equal to the sum of each density times the volume fraction of each component. For example, for a ternary fluid, the density of the ternary fluid may be equal to the sum of the products of the respective density and the volume fraction of the components in the ternary fluid. The reciprocal of the density of the multicomponent fluid may be equal to the sum of the respective mass fractions and densities of the components in the multicomponent fluid. For example, for a three-component fluid, the reciprocal of the density can be determined according to the above equation [16].

The above describes the vibration meter 5, in particular the meter electronics 20, and the method 600 and the system 700, using vapor pressure to determine the concentration of a component in a multi-component fluid. The concentration of the component can be determined using the measurements provided by the vibration meter 5 alone, although additional measurements can be made such as the static pressure measurements described with reference to FIG. 5. As a result, the information provided by the meter electronics 20 may include not only mass flow and density, but also component concentrations in the multi-component fluid. The field of vibration meters is improving as the measurement capabilities of vibration meters are improved. The areas in which vibration meters are used will also improve as the number of measuring devices required to obtain component concentrations in a multi-component fluid can be reduced, thereby saving costs. In addition, information can be provided in real time and in situ, thereby ensuring that the data accurately represents the multicomponent fluid being measured.

The detailed descriptions of the above embodiments are not intended to be exhaustive descriptions of all embodiments contemplated by the inventors as being within the scope of the present disclosure. Indeed, those skilled in the art will appreciate that certain elements of the above described embodiments may be combined or omitted in various ways to create additional embodiments, and such additional embodiments fall within the scope and teachings of the present disclosure. It will also be apparent to those of ordinary skill in the art that the above described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present disclosure.

Thus, while specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the related art will appreciate. The ideas presented here can be applied to other methods, electronics, systems, and the like. for using vapor pressure to determine the concentrations of components in a multicomponent fluid, and not only to the embodiments described above and shown in the accompanying drawings. Accordingly, the scope of the embodiments described above should be determined from the following claims.

Claims (59)

1. System (700) for using vapor pressure to determine the concentration of a component in a multicomponent fluid, system (700) contains: an electronic instrument (710) communicatively coupled to a transducer (720) to sense a multicomponent fluid, the electronic instrument (710) is configured to: determine the first vapor pressure, the first vapor pressure is the vapor pressure of the first component of the multicomponent fluid; determine the second vapor pressure, the second vapor pressure is the vapor pressure of the second component of the multicomponent fluid; determine the multi-component vapor pressure, and the multi-component vapor pressure is the vapor pressure of the multi-component fluid, based on the gain of the excitation signal provided to the transmitter (720); and determine the concentration of at least one of the first component and the second component, based on the multi-component vapor pressure, the first vapor pressure and the second vapor pressure. 2. System (700) according to claim 1, wherein the electronic instrument (710) configurable to determine the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure and the second vapor pressure, contains an electronic instrument (710) configurable to use the equations:

; and

; where: P _m is the multi-component vapor pressure and is the sum of the pressures exerted by each component of the multi-component fluid, which is a two-component fluid;

,

are respectively the first vapor pressure and the second vapor pressure when the first component and the second component are pure fluids; and

,

are, respectively, the mole fractions of the first and second components in the two-component fluid. 3. System (700) according to claim 1, wherein the electronic instrument (710) configurable to determine the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure and the second vapor pressure, contains an electronic instrument (710) configurable to determine the concentrations of the first component, the second component and the third component using the equations:

;

;

; and

; where:

is a multi-component vapor pressure of a multi-component fluid, where the multi-component fluid is a three-component fluid;

and

are the respective mole fractions of the first component, the second component, and the third component of the ternary fluid;

and

are respectively the first vapor pressure, the second vapor pressure and the third vapor pressure when the first component, the second component and the third component are pure fluids;

is the molecular weight of the ternary fluid;

,

and

are the respective molecular weights of the first component, the second component and the third component;

,

and

are the respective mass fractions of the first component, the second component and the third component in the ternary fluid and are respectively equal to

,

and

;

,

and

are the respective densities of the first component, the second component, and the third component of the ternary fluid; and

is the density of the ternary fluid. 4. System (700) according to one of any of the preceding paragraphs. 1-3, wherein the electronic instrument (710) is further configured to determine the density of the multicomponent fluid in the transmitter (720) based on the sensor signals provided by the transmitter (720). 5. System (700) according to one of any of the preceding paragraphs. 1-4, wherein the electronic instrument (710) is further configured to determine the true vapor pressure of the multicomponent fluid based on the static pressure of the multicomponent fluid in the transducer (720). 6. System (700) according to one of any of the preceding paragraphs. 1-5, wherein the electronic device (710) is the measuring electronic device (20), and the measuring transducer (720) is the measuring unit (10) of the vibration meter (5). 7. A method for using vapor pressure to determine the concentration of a component in a multi-component fluid, the method comprising the steps of: determining a first vapor pressure, the first vapor pressure being the vapor pressure of the first component of the multicomponent fluid; determining a second vapor pressure, the second vapor pressure being the vapor pressure of the second component of the multicomponent fluid; using a transmitter having a multi-component fluid to determine the multi-component vapor pressure, the multi-component vapor pressure is the vapor pressure of the multi-component fluid based on the gain of the drive signal provided to the transmitter; and determining the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure. 8. The method of claim 7, wherein determining the concentration of at least one of the first component and the second component based on the multi-component vapor pressure, the first vapor pressure, and the second vapor pressure comprises the step of using the equations:

; and

; where: P _m is the multi-component vapor pressure and is the sum of the pressures exerted by each component of the multi-component fluid, which is a two-component fluid;

,

are respectively the first vapor pressure and the second vapor pressure when the first component and the second component are pure fluids; and

,

are, respectively, the mole fractions of the first and second components in the two-component fluid. 9. The method according to claim 7, wherein determining the concentration of at least one of the first component and the second component based on the multicomponent vapor pressure, the first vapor pressure and the second vapor pressure comprises the step of determining the concentrations of the first component, the second component and third component using the equations:

;

;

; and

; where:

is a multi-component vapor pressure of a multi-component fluid, where the multi-component fluid is a three-component fluid;

and

are the respective mole fractions of the first component, the second component, and the third component of the ternary fluid;

and

are respectively the first vapor pressure, the second vapor pressure and the third vapor pressure when the first component, the second component and the third component are pure fluids;

is the molecular weight of the ternary fluid;

,

and

are the respective molecular weights of the first component, the second component and the third component;

,

and

are the respective mass fractions of the first component, the second component and the third component in the ternary fluid and are respectively equal to

,

and

;

,

and

are the respective densities of the first component, the second component, and the third component of the ternary fluid; and

is the density of the ternary fluid. 10. The method according to one of any of the above paragraphs. 7-9, further comprising determining the density of the multicomponent fluid in the transmitter based on the sensor signals provided by the transmitter. 11. The method according to one of any of the above paragraphs. 7-10, further comprising determining the true vapor pressure of the multicomponent fluid based on the static pressure of the multicomponent fluid in the transducer. 12. The method according to one of any of the above paragraphs. 7-11, wherein the measuring transducer is the measuring unit of the vibration meter.

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