Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
  • G01F1/78—Direct mass flowmeters
  • G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
  • G01N9/36—Analysing materials by measuring the density or specific gravity, e.g. determining quantity of moisture
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
  • G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
  • G01F1/78—Direct mass flowmeters
  • G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
  • G01F1/84—Coriolis or gyroscopic mass flowmeters
  • G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
  • G01F1/8436—Coriolis or gyroscopic mass flowmeters constructional details signal processing
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
  • G01F15/005—Valves
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
  • G01F15/06—Indicating or recording devices
  • G01F15/061—Indicating or recording devices for remote indication
  • G01F15/063—Indicating or recording devices for remote indication using electrical means
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L15/00—Devices or apparatus for measuring two or more fluid pressure values simultaneously
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
  • G01L9/0001—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means
  • G01L9/0008—Transmitting or indicating the displacement of elastically deformable gauges by electric, electro-mechanical, magnetic or electro-magnetic means using vibrations

Definitions

• the embodiments described below relate to determining a vapor pressure and, more particularly, using a density measurement of a fluid to verify a vapor pressure.
• Vibrating sensors such as for example, vibrating densitometers and Coriolis flowmeters are generally known, and are used to measure mass flow and other information for materials flowing through a conduit in the flowmeter.
• Exemplary Coriolis flowmeters are disclosed in U.S. Patent 4,109,524, U.S. Patent 4,491,025, and Re. 31,450, all to J.E. Smith et al. These flowmeters have one or more conduits of a straight or curved configuration.
• Each conduit configuration in a Coriolis mass flowmeter for example, has a set of natural vibration modes, which may be of simple bending, torsional, or coupled type.
• Each conduit can be driven to oscillate at a preferred mode.
• the natural vibration modes of the vibrating system are defined in part by the combined mass of the conduits and the material flowing within the conduits.
• a driving force applied to the conduit(s) causes all points along the conduit(s) to oscillate with identical phase or a small“zero offset”, which is a time delay measured at zero flow.
• Coriolis forces cause each point along the conduit(s) to have a different phase.
• the phase at the inlet end of the flowmeter lags the phase at the centralized driver position, while the phase at the outlet leads the phase at the centralized driver position.
• Pickoffs on the conduit(s) produce sinusoidal signals representative of the motion of the conduit(s). Signals output from the pickoffs are processed to determine the time delay between the pickoffs. The time delay between the two or more pickoffs is proportional to the mass flow rate of material flowing through the conduit(s).
• Meter electronics connected to the driver generate a drive signal to operate the driver and determine a mass flow rate and other properties of a material from signals received from the pickoffs.
• the driver may comprise one of many well-known arrangements; however, a magnet and an opposing drive coil have received great success in the flowmeter industry.
• An alternating current is passed to the drive coil for vibrating the conduit(s) at a desired flow tube amplitude and frequency.
• Vapor pressure is an important property in applications which handle flow and storage of volatile fluids such as gasoline, natural gas liquids, and liquid petroleum gas. Vapor pressure provides an indication of how volatile fluids may perform during handling, and further indicates conditions under which bubbles will likely form and pressure will likely build. As such, vapor pressure measurement of volatile fluids increases safety and prevents damage to transport vessels and infrastructure. For example, if the vapor pressure of a fluid is too high, cavitation during pumping and transfer operations may occur. Furthermore, vessel or process line vapor pressure may potentially rise beyond safe levels due to temperature changes. It is therefore often required that vapor pressure be known prior to storage and transport.
• a vapor pressure is determined by capturing samples and removing them to a laboratory for testing to determine the value from the sample. This poses difficult issues for regulatory fuel quality standards enforcement because of the delay in obtaining final results, the cost of maintaining a lab, and the safety and legal evidence vulnerabilities associated with sample handling.
• the meter electronics comprises a processing system communicatively coupled to a meter assembly having the fluid.
• the processing system is configured to determine a vapor pressure of the fluid by detecting a phase change of the fluid in the meter assembly, measure a density of the fluid based on the resonant frequency of the meter assembly, derive a vapor pressure from the measured density, and compare the determined vapor pressure with the derived vapor pressure.
• a method for using a density measurement of a fluid to verify a vapor pressure comprises determining a vapor pressure of the fluid by detecting a phase change of the fluid in a meter assembly, measuring a density of the fluid based on the resonant frequency of the meter assembly, deriving a vapor pressure from the measured density, and comparing the determined vapor pressure with the derived vapor pressure.
• ASPECTS ASPECTS
• a meter electronics (20) for using a density measurement of a fluid to verify a vapor pressure comprises a processing system (200)
• the processing system (200) is configured to determine a vapor pressure of the fluid by detecting a phase change of the fluid in the meter assembly (10), measure a density of the fluid based on a resonant frequency of the meter assembly (10), derive a vapor pressure from the measured density, and compare the determined vapor pressure with the derived vapor pressure.
• the fluid is a multi-component fluid comprised of hydrocarbon components.
• hydrocarbon components are comprised of at least two of propane, butane, and hexane.
• the processing system (200) being configured to derive the vapor pressure from the measured density comprises the processing system (200) being configured to utilize previously determined correlations between a plurality of vapor pressures and a plurality of densities.
• the processing system (200) being configured to utilize previously the determined correlations between the plurality of vapor pressures and the plurality of the densities comprises the processing system (200) being configured to interpolate between the previously determined correlations.
• the processing system (200) being configured to compare the determined vapor pressure with the derived vapor pressure comprises the processing system (200) being configured to determine if the determined vapor pressure is within a predetermined range of the derived vapor pressure.
• the processing system (200) is further configured to determine the vapor pressure using a drive gain.
• a method for using a density measurement of a fluid to verify a vapor pressure comprises determining a vapor pressure of the fluid by detecting a phase change of the fluid in a meter assembly, measuring a density of the fluid based on a resonant frequency of the meter assembly, deriving a vapor pressure from the measured density, and comparing the determined vapor pressure with the derived vapor pressure.
• the fluid is a multi-component fluid comprised of hydrocarbon components.
• the hydrocarbon components are comprised of at least two of propane, butane, and hexane.
• deriving the vapor pressure from the measured density comprises utilizing previously determined correlations between a plurality of vapor pressures and a plurality of densities.
• utilizing previously the determined correlations between the plurality of vapor pressures and the plurality of the densities comprises interpolating between the previously determined correlations.
• comparing the determined vapor pressure with the derived vapor pressure comprises determining if the determined vapor pressure is within a
• the method further comprises determining the vapor pressure using a drive gain.
• FIG.1 shows a vibratory meter 5.
• FIG.2 is a block diagram of the meter electronics 20 of vibratory meter 5.
• FIG.3 shows a graph 300 illustrating a relationship between a drive gain and a gas-liquid ratio that can be used to determine a vapor pressure using a vapor pressure meter factor.
• FIG.4 shows a graph 400 illustrating how a static pressure of a fluid in a vibratory meter may be used to determine a vapor pressure.
• FIG.5 shows a system 500 for determining a vapor pressure of a fluid.
• FIG.6 shows a graph 600 illustrating a vapor pressure of a multi-component fluid.
• FIG.7 shows a method 700 for using a density measurement of a fluid to verify a vapor pressure.
• FIGS. 1 - 7 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of using a density measurement of a fluid to verify a vapor pressure.
• 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 multiple variations of using the density measurement of the fluid to verify the vapor pressure. 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 vibratory meter 5.
• the vibratory meter 5 comprises a meter assembly 10 and meter electronics 20.
• the meter assembly 10 responds to mass flow rate and density of a process material.
• the meter electronics 20 is connected to the meter assembly 10 via leads 100 to provide density, mass flow rate, temperature information over path 26, and/or other information.
• the meter assembly 10 includes a pair of manifolds 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel conduits 130 and 130', driver 180, resistive temperature detector (RTD) 190, and a pair of pickoff sensors 170l and 170r.
• Conduits 130 and 130' have two essentially straight inlet legs 131, 131' and outlet legs 134, 134', which converge towards each other at conduit mounting blocks 120 and 120'.
• the conduits 130, 130' bend at two symmetrical locations along their length and are essentially parallel throughout their length.
• Brace bars 140 and 140' serve to define the axis W and W' about which each conduit 130, 130’ oscillates.
• conduit mounting blocks 120 and 120' are fixedly attached to conduit mounting blocks 120 and 120' and these blocks, in turn, are fixedly attached to manifolds 150 and 150'. This provides a continuous closed material path through meter assembly 10.
• the process material Upon exiting the conduits 130, 130', the process material is recombined in a single stream within the mounting block 120’ having a surface 121’ and the manifold 150' and is thereafter routed to outlet end 104' connected by the flange 103' having holes 102' to the process line (not shown).
• the conduits 130, 130' are selected and appropriately mounted to the conduit 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 go through the brace bars 140, 140'.
• RTD 190 is mounted to conduit 130' to continuously measure the temperature of the conduit 130’. The temperature of the conduit 130’ and hence the voltage appearing across the RTD 190 for a given current passing
• the temperature dependent voltage appearing across the RTD 190 is used in a well-known method by the meter electronics 20 to compensate for the change in elastic modulus of the conduits 130, 130' due to any changes in conduit temperature.
• the RTD 190 is connected to the meter electronics 20 by lead 195.
• Both of the conduits 130, 130' are driven by driver 180 in opposite directions about their respective bending axes W and W' and at what is termed the first out-of- phase bending mode of the flow meter.
• This driver 180 may comprise any one of many well-known arrangements, such as a magnet mounted to the conduit 130' and an opposing coil mounted to the conduit 130 and through which an alternating current is passed for vibrating both conduits 130, 130’.
• a suitable drive signal is applied by the meter electronics 20, via lead 185, to the driver 180.
• the meter electronics 20 receives the RTD temperature signal on lead 195, and the left and right sensor signals appearing on leads 100 carrying the left and right sensor signals 165l, 165r, respectively.
• the meter electronics 20 produces the drive signal appearing on lead 185 to driver 180 and vibrate conduits 130, 130'.
• the meter electronics 20 processes the left and right sensor signals and the RTD signal to compute the mass flow rate and the density of the material passing through meter assembly 10. This information, along with other information, is applied by meter electronics 20 over path 26 as a signal.
• a mass flow rate measurement can be generated according to the equation:
• the ⁇ t term comprises an operationally-derived (i.e., measured) time delay value comprising the time delay existing between the pick-off sensor signals, such as where the time delay is due to Coriolis effects related to mass flow rate through the vibratory meter 5.
• the measured ⁇ t term ultimately determines the mass flow rate of the flow material as it flows through the vibratory meter 5.
• the ⁇ t0 term comprises a time delay at zero flow calibration constant.
• the ⁇ t0 term is typically determined at the factory and programmed into the vibratory meter 5.
• the time delay at zero flow ⁇ t 0 term will not change, even where flow conditions are changing.
• the flow calibration factor FCF is proportional to the stiffness of the vibratory meter 5.
• n is an average fluid velocity
• r is a density of the fluid
• subscript 1 indicates the inlet
• subscript 3 indicates the outlet
• . is a length of a pipe
• Equation [7] is a version of the Bernoulli equation that accounts for frictional losses associated with traveling through a pipe. As fluid travels through the pipe, the fluid dissipates energy and the pressure drops across a given length of pipe. This loss in pressure is unrecoverable because energy from the fluid has been consumed through frictional losses. Accordingly, the following equation may account for this loss: This relationship can be applied to the exemplary pipe described above with reference to equation [2]. When the fluid moves from the inlet to midway between the inlet and the outlet, there is a change in velocity to conserve the mass flow rate.
• a vibratory meter such as a Coriolis meter, may be inserted into a pipeline that has a diameter that is different than a diameter of a conduit or conduits in the vibratory meter. As a result, when outgassing is detected in the vibratory meter, the pressure measured in the pipeline may not be a vapor pressure of the fluid in the vibratory meter.
• Meter electronics drive gain
• FIG.2 is a block diagram of the meter electronics 20 of vibratory meter 5.
• the vibratory meter 5 provides various measurement values that may be outputted including one or more of a measured or averaged value of mass flow rate, volume flow rate, individual flow component mass and volume flow rates, and total flow rate, including, for example, both volume and mass flow of individual flow components.
• the vibratory meter 5 generates a vibrational response.
• the vibrational response is received and processed by the meter electronics 20 to generate one or more fluid measurement values.
• the values can be monitored, recorded, saved, totaled, 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. Although these components are shown as distinct blocks, it should be understood that the meter electronics 20 can be comprised of various combinations of integrated and/or discrete components.
• the interface 201 is configured to communicate with the meter assembly 10 of the vibratory meter 5.
• the interface 201 may be configured to couple to the leads 100 (see FIG.1) and exchange signals with the driver 180, pickoff sensors 170l and 170r, and RTDs 190, for example.
• the interface 201 may be further configured to
• the processing system 203 can comprise any manner of processing system.
• the processing system 203 is configured to retrieve and execute stored routines in order to operate the vibratory meter 5.
• the storage system 204 can store routines including a flowmeter routine 205, a valve control routine 211, a drive gain routine 213, and a vapor pressure routine 215.
• the storage system 204 can store measurements, received values, working values, and other information.
• the storage system stores a mass flow (m) 221, a density (r) 225, a density threshold 226, a viscosity (m) 223, a temperature (T) 224, a pressure 209, a drive gain 306, a drive gain threshold 302, a gas entrainment threshold 244, a gas entrainment fraction 248, and any other variables known in the art.
• the routines 205, 211, 213, 215 may comprise any signal noted and those other variables known in the art. Other measurement/processing routines are contemplated and are within the scope of the description and claims.
• a vapor pressure may be determined without using the viscosity 223.
• estimate viscosity based on a pressure drop, or a function relating friction as a function of flow rate.
• the viscosity 223 may be used to calculate a Reynolds number which can then be used to determine a friction factor.
• the Reynolds number and friction factor can be employed to determine a viscous pressure drop in a conduit, such as the conduits 130, 130’s described above with reference to FIG. 1.
• the Reynolds number may not necessarily be employed.
• the flowmeter routine 205 can produce and store fluid quantifications and flow measurements. These values can comprise substantially instantaneous measurement values or can comprise totalized or accumulated values. For example, the flowmeter routine 205 can generate mass flow measurements and store them in the mass flow 221 storage of the storage system 204, for example. The flowmeter routine 205 can generate density 225 measurements and store them in the density 225 storage, for example. The mass flow 221 and density 225 values are determined from the vibrational response, as previously discussed and as known in the art. The mass flow and other measurements can comprise a substantially instantaneous value, can comprise a sample, can comprise an averaged value over a time interval, or can comprise an accumulated value over a time interval.
• the time interval may be chosen to correspond to a block of time during which certain fluid conditions are detected, for example a liquid-only fluid state, or alternatively, a fluid state including liquids and entrained gas.
• certain fluid conditions for example a liquid-only fluid state, or alternatively, a fluid state including liquids and entrained gas.
• other mass and volume flow and related quantifications are contemplated and are within the scope of the description and claims.
• a drive gain threshold 302 may be used to distinguish between periods of flow, no flow, a monophasic/biphasic boundary (where a fluid phase change occurs), and gas entrainment/mixed-phase flow.
• a density threshold 226 applied to the density reading 225 may also be used, separately or together with the drive gain 306, to distinguish gas entrainment/mixed-phase flow.
• Drive gain 306 may be utilized as a metric for the sensitivity of the vibratory meter’s 5 conduit vibration to the presence of fluids of disparate densities, such as liquid and gas phases, for example, without limitation.
• the term drive gain refers to a measure of the amount of power needed to drive the flow tubes to specified amplitude, although any suitable definition may be employed.
• the term drive gain may, in some embodiments, refer to drive current, pickoff voltage, or any signal measured or derived that indicates the amount of power needed to drive the flow conduits 130, 130’ at a particular amplitude.
• the drive gain may be used to detect multi-phase flow by utilizing characteristics of the drive gain, such as, for example, noise levels, standard deviation of signals, damping- related measurements, and any other means known in the art to detect mixed-phase flow. These metrics may be compared across the pick-off sensors 170l and 170r to detect a mixed-phase flow. Detecting a phase change of a fluid
• FIG.3 shows a graph 300 illustrating a relationship between a drive gain and a gas-liquid ratio that can be used to determine a vapor pressure using a vapor pressure meter factor.
• the graph 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 in percentages, although any suitable units and/or ratios may be employed.
• the graph 300 includes plots 330 that are relationships between drive gains and gas-liquid ratios for various flow rates.
• the gas-liquid ratio is an average void fraction value of the plots 330, although any suitable gas-liquid ratio, such as a gas volume fraction (“GVF”) or a gas entrainment fraction, may be employed, and may be based on volume, cross-sectional area, or the like.
• the plots 330 are similar despite being associated with different flow rates.
• a drive gain threshold line 340 that intersects with the plots 330 at about 0.20 percent average void fraction, which may be a reference average void fraction 330a that corresponds to a 40% drive gain.
• the true vapor pressure drive gain 332 corresponds to the fluid in the meter assembly that has a static pressure at which a fluid phase change occurs and has a gas-liquid ratio of zero.
• the plots 330 vary from a drive gain of about 10 percent to drive gain of about 100 percent over a range of average void fractions from 0.00 percent to about 0.60 percent.
• 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 onset of vapor formation can be accurately detected with the drive gain.
• the drive gain of 40% is shown as corresponding to an average void fraction of 0.20 percent, the correspondence may be specific to a process.
• the drive gain of 40% may correspond to other average void fractions in other process fluids and conditions. Different fluids may have different vapor pressures and therefore onset of vapor formation for the fluids may occur at different flow rates. That is, a fluid with a relatively low vapor pressure will vaporize at higher flow rates and a fluid with relatively high vapor pressure may vaporize at lower flow rates.
• the drive gain threshold line 340 may be at alternative/other drive gains. However, it may be beneficial to have the drive gain at 40% to eliminate false detections of entrainment/mixed phase flow while also ensuring that the onset of vapor formation is correctly detected.
• the plots 330 employ a drive gain, but other signals may be used, such as a measured density, or the like.
• the measured density may increase or decrease due to the presence of voids in the fluid.
• the measured density may,
• the 0.20 percent average void fraction value may be the reference average void fraction 330a that corresponds to the 40 percent drive gain value, which may be where the drive gain threshold line 340 intersects with the drive gain axis 320. Accordingly, when a measured drive gain is at 40 percent for a fluid in a meter assembly, such as the meter assembly 10 described above, then an average void fraction of the fluid may be about 0.20 percent.
• the void fraction of about 0.20 percent may correspond to a pressure of the fluid due to gas present in the fluid.
• the void fraction of about 0.20 percent may correspond to, for example, a static pressure value.
• a vapor pressure may be associated with a vapor pressure meter factor.
• the meter assembly may be vibrated while a static pressure is increased or decreased until a fluid phase change is detected.
• a vapor pressure may 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 may correspond to, for example, the static pressure at the drive gain threshold line 340.
• This determined vapor pressure may be adjusted by the vapor pressure meter factor to correspond to the true vapor pressure drive gain 332, which is where a phase change occurs, or the monophasic/biphasic boundary is encountered. Accordingly, although the presence of gas in the fluid may be detected at a static pressure that is different than the true vapor pressure of the fluid, the true vapor pressure may nevertheless be determined.
• the static pressure in the meter assembly may be reduced until the drive gain reaches 40 percent, thereby indicating that the fluid in the meter assembly has an average void fraction of 0.20 percent.
• a processing system such as the processing system 203 described above, may determine that the fluid began to vaporize at a static pressure that is, for example, proportionally higher than the static pressure corresponding to the 40 percent drive gain.
• a true vapor pressure may be associated with a drive gain of about 10%.
• a true vapor pressure may be proportionally lower than the calculated static pressure that is associated with the 40% drive gain.
• True vapor pressure corresponds to a static pressure of the fluid where a fluid phase change occurs, but the gas-liquid ratio is zero.
• the measured drive gain can be used to detect gas, yet still may result in a highly accurate true vapor pressure.
• a dynamic pressure may be increased by, for example, a pump that continues to increase a flow rate until the static pressure drops such that drive gain passes the drive gain threshold line 340.
• this calculated static pressure e.g., an uncorrected vapor pressure
• a vapor pressure meter factor of, for example, 1 psi, to account for the delay in detecting the fluid phase change. That is, the vapor pressure meter factor could be determined and applied to the uncorrected vapor pressure measurement as a function of drive gain to account for the difference in the drive gain at which the gas is detected and the true vapor pressure so as to detect tiny amounts of gas.
• the measured drive gain of 40 percent may correspond to a static pressure of the fluid in the meter assembly that is, for example, 1 psi less than a static pressure corresponding to the drive gain associated with the true vapor pressure. Accordingly, the vibratory meter 5, or meter electronics 20, or any suitable electronics, can determine that the vapor pressure meter factor is 1 psi and add this value to the static pressure associated with the 40 percent drive gain. As a result, the vibratory meter 5 may accurately detect the phase change of the fluid and, therefore, also accurately determine a vapor pressure of the fluid using the drive gain.
• phase change may be detected by acoustic measurement, x-ray-based measurements, optical measurements, etc. Also,
• bypass line that extends vertically in a loop with acoustic and/or optical measurements distributed vertically to determine where the gas first outgasses. This height would then provide the needed input to calculate a vapor pressure of the fluid in the vibratory meter 5, as the following explains.
• FIG.4 shows a graph 400 illustrating how a static pressure of a fluid in a vibratory meter may be used to determine a vapor pressure.
• graph 400 includes a position axis 410 and a static pressure axis 420.
• the position axis 410 is not shown with any particular units of length, but could be in units of inches, although any suitable unit may be employed.
• the static pressure axis 420 is in units of pounds- per-square inch (psi), although any suitable unit may be employed.
• the position axis 410 ranges from an inlet (“IN”) to an outlet (“OUT”) of the vibratory meter.
• the position from IN to OUT may correspond to fluid in, for example, the meter assembly 10 shown in FIG.1.
• the region from IN to about A may correspond to a portion of the meter assembly 10 between the flange 103 to the conduit mounting block 120.
• the region from about A to about G may correspond to the conduits 130, 130’ between the mounting blocks 120, 120’.
• the region from G to OUT may correspond to the portion of the meter assembly 10 from the mounting block 120’ to the flange 103’.
• the fluid in the meter assembly 10 (e.g., in the position ranging from IN to OUT) may not include fluid in, for example, the pipeline in which the meter assembly 10 is inserted.
• the fluid in the meter assembly 10 may be the fluid in the conduits 130, 130’.
• the graph 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 the dynamic pressure– the pressure is assumed to decrease linearly from an inlet to an outlet of a vibratory meter.
• the dynamic pressure change plot 440 may represent an actual pressure in the vibratory meter inserted into the pipeline wherein the diameter of the conduit or conduits of the vibratory meter is less than the diameter of the pipeline.
• An exemplary vibratory meter 5 is shown in FIG.1, although any suitable vibratory meter may be employed. Accordingly, the fluid in the meter assembly, such as the meter assembly 10 described above, may have a reduced static pressure due to an increase in dynamic pressure.
• a vapor pressure line 450 representing a vapor pressure of the fluid in the vibratory meter.
• the dynamic pressure change plot 440 includes a static pressure drop section 440a, a viscous loss section 440b, and a static pressure increase section 440c.
• the dynamic pressure change plot 440 also includes a minimum static pressure 440d.
• the static pressure drop section 440a may be due to an increase in fluid velocity causing a corresponding increase in the dynamic pressure of this section of the vibratory meter.
• the viscous loss section 440b may correspond to a constant diameter portion of the conduit or conduits in the vibratory meter. Accordingly, the viscous loss section 440b may not reflect an increase in fluid velocity and, therefore, may not reflect an increase in a dynamic pressure.
• the static pressure increase section 440c may be due to a decrease in fluid velocity and, therefore, the static pressure decrease during the static pressure drop section 440a may be recovered.
• the static pressure drop section 440a and the static pressure increase section 440c may be static pressure changes in the meter assembly.
• the portion of the dynamic pressure change plot 440 lying below the vapor pressure line 450 may correspond to positions (e.g., from about position E to slightly after position G) where a fluid phase change occurs in a fluid in a meter assembly, such as the meter assembly 10 described above.
• the minimum static pressure 440d is below the vapor pressure line 450. This indicates that the dynamic pressure change plot 440 may be shifted upwards by increasing the static pressure of the fluid in the meter assembly. However, if the static pressure were to be increased by about 5 psi so as to shift the dynamic pressure change plot 440 up until the minimum static pressure 440d lies on the vapor pressure line 450, a fluid phase change may be detected.
• the fluid phase change may be the formation of gas or vapor in the fluid.
• the viscous loss section 440b decreases from a static pressure of about 68 psi at position A to a static pressure of about 55 psi at position G.
• the static pressure of about 55 psi at the position G is less than the vapor pressure line 450, which is about 58 psi.
• the static pressure at the inlet and outlet do not directly correspond to the vapor pressure of the fluid.
• the vapor pressure of the fluid may not be directly determined from a static pressure of the fluid in the pipeline or external of the meter assembly.
• the static pressure in the meter assembly 10 or, more specifically, the conduits 130, 130’ can be accurately determined by, for example, using the pressure measurements at the inlet and the outlet and inputting the dimensions of the vibratory meter 5 (e.g., diameter and length of the conduit 130, 130’).
• a phase change in the fluid in the vibratory meter 5 may need to be induced, which may be caused by varying the static pressure of the fluid in the vibratory meter 5.
• FIG.5 shows a system 500 for determining a vapor pressure of a fluid.
• the system 500 is a bypass that includes a bypass inlet and a bypass outlet that are coupled to a pipeline 501.
• the system 500 includes a pump 510 in fluid communication with an outlet of a vibratory meter 5, illustrated as a Coriolis meter, and the bypass outlet.
• An inlet pressure sensor 520 is in fluid communication with an inlet of the vibratory meter 5 and the bypass inlet.
• An outlet pressure sensor 530 is disposed between the outlet of the vibratory meter 5 and the pump 510 and is in configured to measure a static pressure of the fluid at the outlet of the vibratory meter 5.
• a flow control device 540 which is shown as a valve, is disposed between the bypass inlet and the inlet pressure sensor 520.
• the pump 510 may be any suitable pump that can, for example, increase a velocity of the fluid in the vibratory meter 5.
• the pump 510 may, for example, include a variable frequency drive.
• the variable frequency drive may allow the pump 510 to control a fluid velocity of the fluid in the system 500.
• the variable frequency drive may increase the fluid velocity of the fluid through the vibratory meter 5, although the fluid velocity may be increased by any suitable pump.
• the pump 510 can increase a dynamic pressure of the fluid in the vibratory meter 5 by increasing the fluid velocity.
• the static pressure of the fluid in the vibratory meter 5 may decrease.
• the pump 510 may cause the dynamic pressure change plot 440 to shift downward.
• the pump 510 may induce flashing or outgassing by causing the dynamic pressure change plot 440 to shift downward.
• gas or vapor in the fluid may become a liquid.
• the inlet pressure sensor 520 and the outlet pressure sensor 530 may be any suitable pressure sensor configured to measure any pressure of the fluid.
• the inlet pressure sensor 520 and the outlet pressure sensor 530 may measure a static pressure of the fluid in the system 500. Additionally, or alternatively, the inlet pressure sensor 520 and the outlet pressure sensor 530 may measure a total pressure of the fluid in the system 500.
• a dynamic pressure of the fluid may be determined by taking a difference between the total pressure and the static pressure of the fluid in the system 500 according to equation [3] above.
• the inlet pressure sensor 520 may measure the total pressure and the static pressure of the fluid proximate to, or at, an inlet of the vibratory meter 5.
• the inlet pressure sensor 520 and/or the meter electronics 20 in the vibratory meter 5 may determine the dynamic pressure at the inlet of the vibratory meter 5.
• the flow control device 540 may increase the fluid velocity of the fluid in the system 500, when the flow control device 540’s position is moved from a partially closed position to a fully open position. For example, by decreasing the flow restriction of the system 500 at the inlet of the vibratory meter 5, the velocity of the fluid may increase in accordance with equation [2] above. This can shift the dynamic pressure change plot 440 down so as to induce flashing or outgassing. Conversely, the flow control device 540 can reduce the fluid velocity of the fluid in the system 500 thereby shifting the dynamic pressure change plot 440 up, thereby causing gas or vapors to condense.
• the combination of the flow control device 540 with the pump 510 may provide a preferred process condition by partially closing the flow control device 540 (e.g., to restrict a flow and lower pressure downstream of the flow control device 540) and increasing pump speed (e.g., increasing flow rate) to obtain a desirably lower static pressure and higher velocity.
• the static pressure of the fluid in the vibratory meter 5, or, more particularly, the meter assembly 10 in the vibratory meter 5, may be varied by using the pump 510 or the flow control device 540, or a combination of both, described above, other means of varying the static pressure may be employed.
• a height z of the vibratory meter 5 may be varied. To reduce the static pressure of the fluid in the vibratory meter 5, the height z may be increased. To increase the static pressure of the fluid in the vibratory meter 5, the height z may be decreased.
• the height z of the vibratory meter 5 may be varied by any suitable means, such as a motorized lift between the vibratory meter 5 and the pipeline 501 and bellows between the vibratory meter 5, for example, the flow control device 540 and the pump 510.
• Other means may be employed, as well as a combination of various means (e.g., the pump 510, flow control device 540, and/or the motorized lift).
• a pump may not necessarily be employed. Only the flow control device 540 may be used. The flow control device 540 may be installed in other locations, such as downstream of the vibratory meter 5. Alternatively, the flow control device 540 may not be employed, such as where the pump 510 and/or motorized lift is used. In another alternative example, the meter may be installed in the main line, rather than a bypass. Additionally, or alternatively, only a single pressure sensor may be employed. For example, only the outlet pressure sensor 530 may be employed. The inlet and/or outlet pressure sensors 520, 530 may be located at alternative locations.
• FIG.6 shows a graph 600 illustrating a vapor pressure of a multi-component fluid.
• the multi-component fluid is comprised of hydrocarbons.
• the graph 600 includes a liquid density axis 610 and a logarithmic vapor pressure axis 620, which are respectively in units of kilograms-per-cubic meter (kg/m 3 ) and pounds-per- square inch absolute (psia), although any suitable unit may be employed.
• the graph 600 also includes a density-to-pressure plot 630 illustrating a relationship between the density and vapor pressure of hydrocarbons.
• the density-to-pressure plot 630 is shown as being comprised of a propane density-to-pressure plot 630a, a butane density-to- pressure plot 630b, and a hexane density-to-pressure plot 630c.
• the temperature of the multi-component fluid lies in a range of 34 oC to 48 oC.
• the density of the fluid may lie between the density of the two components. This density can be used to determine a vapor pressure for the mixture.
• the density of the propane and butane fluid can be correlated with the vapor pressure by interpolation.
• a linear interpolation may be used to estimate the vapor pressure of the mixture from the density.
• the multi-component fluid comprised of propane and butane may have a density of about 500 kg/m 3 , which may correspond to a vapor pressure of about 130 psia. This vapor pressure can be used to verify a vapor pressure determined by detecting a phase change in a meter assembly as described above.
• FIG.6 may be a simplified representation with only three components.
• Alternative density-to-temperature plots may differ. For example, more components typical of a crude oil or processed hydrocarbon and the characteristics may be employed, which may result in alternative density-to-temperature plots.
• propane(s) if additional propane(s) are employed, an increase in a vapor pressure may be observed, but the density may be similar if the other components are heavier (e.g., crude oil). Regardless, a general relationship may remain true that, for example, the higher the density the lower the vapor pressure and vice versa.
• a slope or curve of the alternative plot may not always be constant.
• FIG.7 shows a method 700 for using a density measurement of a fluid to verify a vapor pressure.
• the method 700 determines a vapor pressure of a fluid by detecting a phase change of the fluid in the meter assembly in step 710.
• the meter assembly employed by the method 700 may be the meter assembly 10 described above, although any suitable meter assembly may be employed.
• the method 700 measures a density of the fluid based on a resonant frequency of the meter assembly.
• the density of the fluid such as a multi-component fluid, may be determined by, for example, determining a resonant frequency of the meter assembly and determining a corresponding density associated with the resonant frequency.
• the method 700 in step 730, derives a vapor pressure from the measured density.
• the method 700 compares the determined vapor pressure with the derived vapor pressure.
• the vapor pressure of the fluid may be determined by, for example, varying the total or static pressure of the fluid in the meter assembly 10 until a fluid phase change is detected.
• the static pressure of the fluid may be decreased until vapor is no longer detected.
• the static pressure may be increased until vapor is detected.
• the fluid phase change may be detected by any suitable means, such as, for example, based on the sensor signals, such as detecting a change in a drive gain or drive signal as discussed above with reference to FIG.3.
• the vibratory meter 5, or electronics coupled to the vibratory meter 5 may determine the pressure at the inlet and/or outlet of the meter assembly 10.
• the inlet pressure sensor 520 may measure the static pressure of the fluid at the inlet of the meter assembly 10
• the outlet pressure sensor 530 may measure the static pressure of the fluid at the outlet of the meter assembly 10.
• the inlet static pressure and/or the outlet static pressure may be associated with the fluid phase change.
• the inlet static pressure and the outlet static pressure can be used in equation [7] above to determine a static pressure in the meter assembly.
• the outlet pressure may be P 1
• P 2 may be a pressure of the fluid in the meter assembly.
• the height related terms, pgz 1 and pgz 2 may be used to account for change in height of the fluid in the meter assembly due to, for example, conduit geometry.
• bow shaped conduits, such as those of the meter assembly 10 described above may have an elevation change.
• the dynamic velocity terms may similarly be solved for by
• pressure drop term may also be determined.
• the derivation of the vapor pressure may be based on previously determined correlations between a plurality of vapor pressures and densities.
• the plurality of vapor pressures may include vapor pressure measurements of various hydrocarbons.
• the densities may be the densities of the hydrocarbons.
• FIG. 6 shows hydrocarbons of propane, butane, and hexane, more or fewer and alternative hydrocarbons may be employed.
• the correlations between the plurality of vapor pressures and the densities may be the density-to-pressure plot 630, which, as illustrated in FIG.6, is comprised of a propane density-to-pressure plot 630a, a butane density-to-pressure plot 630b, and a hexane density-to-pressure plot 630c.
• the correlations between the plurality of vapor pressures and the densities may also include interpolations, such as formulas, data points, or the like, between the propane density-to-pressure plot 630a, butane density-to- pressure plot 630b, and/or hexane density-to-pressure plot 630c.
• interpolations may correspond to correlations between the plurality of vapor pressures and the densities for multi-component fluids.
• an interpolation between the propane density-to-pressure plot 630a and the butane density-to-pressure plot 630b may correlate a density of 500 kg/m 3 to a vapor pressure of about 120 psia.
• This interpolation may correlate densities and vapor pressures for a mixture of propane and butane.
• density-to-pressure plots alternative to those shown in FIG.6 may differ depending on the number and concentration of components.
• the vapor pressure of a liquid is a function of temperature and composition, and the density of a liquid is a strong function of temperature and composition
• the vapor pressure of a pure or multi-component liquid can be correlated to its density. This is shown on FIG.6, where the vapor pressure of selected hydrocarbons is plotted against their liquid density.
• the density and temperature measurements from a Coriolis meter could be used to determine the approximate saturation pressure of a hydrocarbon. This correlation can be used as an indirect measure of the vapor pressure and would be used as a quality check for the direct pressure measurements described above with reference to FIGS.3-5.
• a calibration service that fits a specific application, fluid(s), and process conditions could be offered.
• the density (of pure or multi-component liquids) could be correlated to the vapor pressure, potentially eliminating the need of taking pressure measurements.
• Typical composition of hydrocarbon liquids from midstream plants contain a mixture of around 30 components. Using only density to determine the vapor pressure of the mixture having 30
• the components may be sufficiently accurate.
• the vapor pressure may be sufficiently accurate if the expected change in concentration of each component is minimal.
• the above describes the vibratory meter 5, in particular the meter electronics 20, and a method 700 of using density to verify a vapor pressure. Accordingly, the accuracy of the vapor pressure may be assured.
• the density may include densities of multi- component fluid. Therefore, when the vapor pressure is comprised of a plurality of partial vapor pressures, the densities may still be used to verify the vapor pressure.
• the density may be determined in a vibratory meter 5, which may also determine the vapor pressure, the vapor pressure may be verified within, for example, the meter electronics 20, prior to providing the vapor pressure over path 26.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Signal Processing (AREA)
• Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Biochemistry (AREA)
• Analytical Chemistry (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Measuring Volume Flow (AREA)
• Measuring Fluid Pressure (AREA)

Priority Applications (12)

Applications Claiming Priority (1)

Publications (1)

Family

ID=66248672

Family Applications (1)

Country Status (11)

Families Citing this family (2)

Citations (4)

Family Cites Families (13)

• 2019
  • 2019-04-03 MX MX2021010881A patent/MX2021010881A/es unknown
  • 2019-04-03 SG SG11202110722VA patent/SG11202110722VA/en unknown
  • 2019-04-03 BR BR112021018484-8A patent/BR112021018484B1/pt active IP Right Grant
  • 2019-04-03 US US17/438,746 patent/US12038453B2/en active Active
  • 2019-04-03 CN CN201980095167.1A patent/CN113677960A/zh active Pending
  • 2019-04-03 WO PCT/US2019/025535 patent/WO2020204920A1/en unknown
  • 2019-04-03 JP JP2021559032A patent/JP2022527984A/ja active Pending
  • 2019-04-03 AU AU2019440152A patent/AU2019440152B2/en active Active
  • 2019-04-03 EP EP19718940.0A patent/EP3948176A1/en active Pending
  • 2019-04-03 KR KR1020217035664A patent/KR102704826B1/ko active IP Right Grant
  • 2019-04-03 CA CA3135824A patent/CA3135824C/en active Active
• 2023
  • 2023-11-30 JP JP2023202795A patent/JP2024023472A/ja active Pending

Patent Citations (5)

Also Published As

Similar Documents

Legal Events