Positive Displacement Meters Research Articles

Evaluation of the Influence of Water Content in Oil on the Metrological Performance of Oil Flow Measurement Systems

According to current Brazilian regulations, if the volumes of oil produced used as a reference for the payment of government shares and third parties contain a water content greater than 2% v/v, these volumes must be arbitrarily increased between 1.44% and 10.89% due exclusively to water content, which has caused operational problems for oil companies such as differences between volumes produced and volumes sold, and additional payments from government shares and third parties. This study aimed to evaluate the metrological performance of oil measurement systems with ultrasonic, Coriolis and positive displacement flow meters when subjected to varied water content, fluid temperature and flow rate conditions using the Design of Experiments and the Response Surface Methodology. The analysis of variance showed that the models presented good fits for the ultrasonic meter (coefficient of determination R2 of 97.96%, p-value of 0.001, and a standard deviation of 5.89 × 10−5); Coriolis meter (R2 of 90.91%, p-value of 0.037, and a standard deviation of 5.88 × 10−5); and positive displacement meter (R2 of 99.07%, p-value of 0.000, and a standard deviation of 4.85 × 10−5). The results of the experiments carried out indicate that the contribution of each parameter analyzed to the metrological performance of the measurement system varies depending on the measurement technology used by the flow meter. However, the fluid temperature proved to be a relevant parameter common to all flow measurement technologies evaluated. All measuring technologies evaluated were influenced by water content in the range of 0% to 10% v/v, with the measurement error being less than 0.2% when compared to a standard positive displacement type meter in almost all experimental conditions. The Coriolis-type flow meter was the one that presented the smallest error among the measuring technologies evaluated.

Risk analysis in conformity assessment of positive displacement flowmeter

Volume measurement of manufactured liquids and liquid raw materials carried out by road tankers (RT) is usual and has economic relevance, justifying the need to ensure metrological reliability. It requires some actions, including choosing suitable standards. In this scenario and considering the practice for type evaluation of measuring instruments, the article proposes a case study, analyzing performance data from a positive displacement meter, a measurement principle widely used as a standard in RT verifications. Current criteria of legal metrology were used: for the 0.3 accuracy class, the maximum permissible error (MPE) is 0.2%. The meter was tested with three different fluids (with different viscosities), and measurement errors were contrasted with the MPE specification, being considered compliant in all situations. On the other hand, risk analysis tools for conformity assessment were incorporated (JCGM 106) based on the different consumer risks, the formulated decision rule, and the measurement uncertainty. Even though, when including the risk analysis, the flowmeter was considered non-compliant, showing the need for a better basis decision using measurement uncertainty in legal metrology actions.

Uncertainty Estimation for the Liquid Hydrocarbons Measurement in Static and Dynamic Measurement Systems: A Colombian Case Study

Summary To evaluate the level of accuracy of more than 500 measurement systems of liquid hydrocarbons in Colombia, a computer tool is currently used to calculate the uncertainty of measurement, applying the Guide to the Expression of Uncertainty in Measurement (GUM) method described in JCGM100 (2008). Taking into account that the selected method presents limitations by assuming that the output variable always has a Gaussian probability distribution and that the model that represents the measurand should preferably be linear, there is a risk that some of these conditions will not be met for the current application. Therefore, this present work describes a comparison between the uncertainty assessment performed according to the GUM uncertainty framework and the Monte Carlo method (MCM) to confirm that the GUM method is valid for the uncertainty measurement evaluation of the measurements under study. This comparison was made from actual data sets associated with two selected examples: liquid hydrocarbon measurement with a vertical fixed-top tank and dynamic measurement with a positive displacement meter. As a result, the maximum difference between the GUM and MCM uncertainties obtained during the tests was 0.003% relative to the volume measured in the vertical tank example. In the case of the dynamic measurement with a positive displacement meter, it was 0.0004% relative to the volume. These differences were less than the numerical tolerance established according to the Monte Carlo adaptive procedure; therefore, it was possible to conclude that the application of GUM is adequate for the examples evaluated and others with similar operating conditions.

A high-pressure bi-directional cycloid rotor flowmeter.

The measurement of the flow rate of various liquids and gases is critical in industrial automation. Rotary positive displacement meters (rotary PD meters) are highly accurate flowmeters that are widely employed in engineering applications, especially in custody transfer operations and hydraulic control systems. This paper presents a high pressure rotary PD meter containing a pair of internal cycloid rotors. It has the advantages of concise structure, low pressure loss, high accuracy and low noise. The curve of the internal rotor is designed as an equidistant curtate epicycloid curve with the external rotor curve as its conjugate. The calculation method used to determine the displacement of the cycloid rotor flowmeter is discussed. A prototype was fabricated, and experiments were performed to confirm measurements over a flow range of 1–100 L/min with relative errors of less than ±0.5%. The pressure loss through the flowmeter was about 3 bar at a flow rate of 100 L/min.

Flow measurement of liquid hydrocarbons with positive displacement meters: the correction for slippage

In the oil industry, the economical and fiscal impact of the measurements accuracy on the custody transfer operations implies fulfilling strict requirements of legal metrology. In this work, we focus on the positive displacement meters (PD meters) for refined liquid hydrocarbons. The state of the art of the lack of accuracy due to slippage flow in these meters is revised. The slippage flow due to the pressure drop across the device has been calculated analytically by applying the Navier–Stokes equation. No friction with any wall of the slippage channel has been neglected and a more accurate formula than the one found in the literature has been obtained. PD meters are calibrated against a bidirectional prover in order to obtain their meter factor which allows correction of their indications. Instead of the analytical model, an empirical one is proposed to explain the variation of the meter factor of the PD meters with flow rate and temperature for a certain hydrocarbon. The empirical model is based on the historical calibration data, of 9 years on average, of 25 m with four types of refined hydrocarbon. This model has been statistically validated by linear least-squares fitting. By using the model parameters, we can obtain the meter factor corresponding to different conditions of temperature and flow rate from the conditions in which the devices were calibrated. The flow parameter is such that a 10% flow rate variation implies a meter factor variation lower than 0.01%. A rule of thumb value for the temperature parameter is 0.005% per degree Celsius. The model residuals allow surveillance of the device drift and quantifying its contribution to the meter factor uncertainty. The observed drift is 0.09% at 95% confidence level in the analyzed population of meters.

Calibration of prover tanks making use of a Coriolis mass flow meter as the master meter

Calibration of volumetric proving tanks can be done using different methods. For the calibration of large proving tanks the master meter method can be used as a good alternative to the volumetric transfer method or the gravimetric method. When the master meter method is used in most cases a positive displacement meter is used. A better option is to make use a Coriolis mass flow meter as the master meter. Test data is presented of a calibration of a proving tank with a nominal volume of 500 L. Small repeatability figures can be obtained of consecutive calibration runs with a Coriolis mass flow meter. Also the linearity of the meter factor curve of the Coriolis mass flow meter makes this a better option for the master meter method.

Final report on APMP.M.FF-K2 bilateral comparison: Hydrocarbon liquid flow

This bilateral comparison was carried out in the field of liquid hydrocarbon flow following the Guidelines for CIPM Key Comparisons. This APMP.M.FF-K2 comparison involved two laboratories: Center for Measurement Standards (CMS, Chinese Taipei) and Vietnam Measurement Institute (VMI), which are both national standard calibration laboratories.The bilateral comparison was conducted using light liquid hydrocarbon across a flow range of 5 L s−1 to 30 L s−1. A Kral positive displacement meter served as the transfer standard. The Strouhal number and Reynolds number served as the key parameters for expressing the laboratories' measurements of volume and flowrate.The En value of the VMI test results with reference to CMS was 0.28.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report on international key comparison of liquid hydrocarbon flow facilities, CCM-FF-K2

This international key comparison was carried out in the field of liquid hydrocarbon flow. The intercomparison initially involved nine laboratories each designated as national standard calibration laboratories. The comparison was carried out using the BIPM guidelines for key comparisons and is included in the BIPM database to support the capability statements of the institutes as part of the MRA. The intercomparison was designated as being comparison CCM-FF-K2 by WGFF.The key comparison was carried out using light liquid hydrocarbon across a flow range 5 l/s to 30 l/s. Two meters, a Kral positive displacement meter and a turbine meter, were used in the intercomparison package; however, the primary comparison used the Kral positive displacement meter. Strouhal and Reynolds numbers were used as the key parameters to express the laboratories' (dynamic) measurement of volume and flowrate.Six laboratories finally provided results to allow the calculation of a KCRV (based on Strouhal number), and all six sets of results were consistent with the KCRV. The deviations from the KCRV using the Kral meter lay within a band of ±0.026%.Main text.To reach the main text of this Paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Development of Hydrocarbon Flow Calibration Facility as a National Standard

A new primary standard for hydrocarbon flow measurements has been constructed at National Metrology Institute of Japan (NMIJ). The facility was designed for the calibration of hydrocarbon flowmeters in the flow rate range between 3 and 300 m3/h. The expanded uncertainty is estimated to be 0.03 % for volumetric flow rate and 0.02 % for mass flow rate (coverage factor: k = 2). The primary standard is based on a static and gravimetric method with a flying start and finish. The facility consists of two test rigs using kerosene and light oil as working fluids. The test lines for the flowmeters are 50, 100 and 150 mm in diameter and three servo positive displacement meters are used as working standards. To verify the calibration performance, a Coriolis flowmeter, a turbine meter and a positive displacement flowmeter have been calibrated at both test rigs. Furthermore, an international comparison with SP, Swedish National Testing Research Institute, was carried out. A screw-type positive displacement flowmeter was selected as the transfer standard and was calibrated at NMIJ and SP. The result shows that the two national standards at the two institutes agree within the quoted expanded uncertainties.

Sizing the Customer's Meter

This article discusses how to properly select the right water meter, including sizing it, for the customer. The article discusses how the engineer should use utility‐approved meter manufacturer's specifications to determine pressure loss, range of accuracy, and capacity. Topics covered include: distribution of flow rates; positive displacement meters; fire line meters; turbine‐plate strainers; and meter arrangements for fire services. Several AWWA Manuals and Standards are called out as references.

Automated Meter Reading a Boon for North Carolina City

This article describes how the Public Works Department of the City of Conover, North Carolina, converted their meter‐reading system to an automated system (AMR). They also replaced all 3/4 inch meters with new positive displacement meters, which would be beneficial in the continued evaluation of the new AMR system and possibly increase sales revenues by providing more accurate readings.

Accuracy Key to Testing Meters

This article discusses when to replace residential water meters and refers to the 1998 Optimum Meter Age Study. The study indicated that not only the accuracy and performance of meters needs to be tested, but also the accuracy of the testing methods and devices used needs to be measured. It states that the accuracy of positive displacement meters deteriorates over time because of accumulated registration, and disk nutations or piston oscillations in the measuring chamber of the meter create wear and tear that has a negative effect on accuracy and indicated consumption. Criteria for analyzing the method used to bench‐test meters after removal from the distribution system are given, along with criteria for analyzing the test results. The effect of meter change notices left at customers' property when meter changes were performed is discussed, and a graph showing the most cost‐effective time frame for residential meter replacement is given.

Using statistical models to detect leaks in underground storage tanks

In modern service stations, intermediate grades of gasoline are formed by blending different volumes of unleaded and super unleaded gasolines stored in underground storage tanks. The volumes displaced from these coupled tanks can be modeled in a two-dimensional model as a function of the volumes dispensed through the flow meters located at the pumps (or positive flow displacement meters). The intercepts in these models represent the sizes of leaks in the respective underground storage tanks. Inferences on the vector of intercepts are discussed based on a regression model, a measurement-error model and a sequential model. In the last model, bivariate control charts are used to monitor the leak status of the tanks. Copyright © 2000 John Wiley & Sons, Ltd.

Effects of water in oil and oil in water on single-phase flowmeters

The effect of two-phase flow on the performance of a range of single-phase flowmeters has been investigated experimentally using the National Standard Multiphase Flow facilities at NEL. The flowmeters tested were 2-inch and 4-inch positive displacement meters, venturi meters, helicoidal and flat-bladed turbine meters, 2-inch U-tube, 3-inch and 1.5-inch straight tube Coriolis meters and a 4-inch vortex shedding meter. The flowmeters were tested in oil flow with water and water flow with oil. The second component fractions were varied from 3% up to 15% by volume. The aim of the project was to quantify the effect of second-phase fluid components on the basic uncertainty of a range of single-phase. These tests have provided evidence of the suitability of particular flowmeters for two-component flow applications. Comparisons have been made between generic type and size of flowmeter. The oil-in-water and water-in-oil tests indicated that the uncertainty in the outputs of the flowmeters tested were generally within ±1% relative to the reference flowrates, although some errors as high as 5–10% were also observed. Most of the measurements from the turbine flowmeters and the positive displacement flowmeters were within ±0.4% of the reference flowrates.

Effects of gas leaks in oil flow on single-phase flowmeters

The effect of gas entrainment in oil on the performance of a range of single-phase flowmeters has been investigated experimentally using the National Standard Multiphase Flow facilities at NEL. The flowmeters tested were 4-inch and 2-inch positive displacement, venturi, helicoidal and flat-bladed turbine meters and 2-inch U-tube and 1.5-inch straight tube Coriolis meters. The flowmeters were tested in oil flow with gas fractions up to 15% by volume. The aim of the project was to quantify the effect of second-phase fluid components on the basic uncertainty of a range of single-phase flowmeters and, as a consequence, identify which generic types of single-phase flowmeter were most suitable in applications where such components may be present. These tests have provided evidence of the suitability of particular flowmeters for two-component flow applications. Comparisons have been made between generic type and size of flowmeter. At low gas fractions, the positive displacement and venturi flowmeters were more accurate than the other meters and estimated the total flowrate to within ±2%. Over 9% gas fraction, there was an improvement to the response from some of the flowmeters with increasing gas fractions. This was considered to be indicative of improved mixing in the flow.

Care and Feeding of Steam-Injection EOR Projects

Steam-enhanced recovery methods have been the overwhelming EOR champions since their inception in the mid-1960`s. About 6 of every 10 EOR barrels produced worldwide are the result of some steam process. Historically most well known in the San Joaquin Valley of California, large steam projects exist in countries around the world, including Venezuela, Canada, Colombia, Indonesia, China, and the CIS. Therefore, one would think that most of the basic problems, such as effective steam-distribution piping systems and accurate methods of metering steam into wells, would have been solved years ago. Unfortunately, this is not the case. In fact, this technology has been woefully lacking compared with its relative importance. This paper summarizes current efforts by the industry to improve metering and distribution of quality steam.

Applied fluid mechanics

Applied fluid mechanics

Positive-displacement meters for liquids

After brief descriptions of the most common industrial types of meter and a review of the relevant literature, various aspects of a typical meter are analysed. These include the effects of temperature, pressure and orientation. A governing equation is derived and the behaviour of calibrators is analysed. Dimensions of a typical meter design are used to obtain values for coefficients in the governing equation and the expansion due to changes in temperature and pressure. Consideration is given to the causes of 'back-slip'. The paper includes a general discussion of instrument accuracy, slippage tests and the use of the derivations for developing a computational prediction.

Water Metering Accuracy Vital to Water Industry

The accurate measurement of water flow is one of the most crucial and vital elements in water operations. This article discusses types of meters, their accuracy, design, and use. Attention is given to positive displacement meters and inference meters.

A Statistical Meter-Proving Method

JPT Forum articles are limited to 1,500 words (including 250 per table orfigure) or a maximum of two pages. Forum articles may present preliminaryresults or conclusions from continuing investigations or may impart generaltechnical information that does not require publication as a full-length paper.Forum articles are subject to approval by an editorial committee. paper. Forumarticles are subject to approval by an editorial committee. Letters to theeditor are published as Dialogue and may cover technical or nontechnicaltopics. SPE-AIME reserves the right to edit letters for style and content. Introduction The general requirement for meter proving is stated in API Standard 1101:"A positive displacement (PD) meter should be proved in its normalinstallation at the expected operating rate of flow, under the pressure andtemperature at which it will normally operate, and on the liquid which it willmeasure in normal condition.... When a meter is measuring several differentliquids, the meter should be proved on each liquid." Examination of API andother industry procedures for proving meters indicates Tat the procedures forproving meters indicates Tat the accepted ways vary greatly. For example, aminimum of five runs for proving the turbine meter was suggested in APIStandard 2534 and a minimum of two runs was mentioned in API Manual ofPetroleum Measurement Standards for proving the Petroleum Measurement Standardsfor proving the PD meters. In industry, Sohio reported using a PD meters. Inindustry, Sohio reported using a 12-run program to prove some PD meters. SunCo. has used a procedure of repeating proving runs until three consecutive runsare within a prescribed tolerance. Another procedure uses 12 runs, theneliminates the highest and lowest readings. The number of proving runs used inthese procedures seems arbitrarily determined. None of the procedures seemsarbitrarily determined. None of the procedures mentions the use of thestatistical procedures mentions the use of the statistical properties of themeter readings to derive the exact properties of the meter readings to derivethe exact runs required. This observation is supported by Bloser of EmersonElectric Co. He stated, "No standard has been set of the frequency ofproving, though it is related directly to the accuracy of a meter and provingsystem." It is true that too few runs will provide an unacceptable level ofaccuracy. Conversely, too many runs will waste time and delay shipment. Theneed for determining an adequate number of runs is apparent This study details a simple procedure designed for meter proving todetermine the exact number of proving runs required, based on the statisticalproving runs required, based on the statistical characteristics of the seriesof meter readings. The meter factor derived from these readings will beaccurate to within the desired tolerance with certain confidence. Analysis of Meter Proving Run Data Considerable proving-run field data (provided by Sun Pipe Line Co.) wereanalyzed. Some observations based on this analysis follow.The series ofmeter counts (or readings) in each calibration does not show any upward ordownward trend under normal operation. Each series appears to be distributedrandomly around its mean level. Typical examples of the series of meter countsare shown in Fig. 1. The mean and estimated standard deviation of the metercounts, as well as its coefficient of variation, also are shown.Using theKolmogorov-Smirnov Tests to check the normality assumption of the series, thehypothesis is rejected at 5% significance level only in one of 27 cases tested.Thus, the probability distribution of the series of meter counts reasonably canbe assumed as normal.The coefficient of variation is inversely proportionalto the net prover volume. Also, proportional to the net prover volume. Also, increasing the ratio of the net prover volume to the flow through the meterwill reduce the coefficient of variation. Development of Meter Factor After each meter calibration, a meter factor is calculated by taking theratio of the adjusted prover volume to the average of meter counts adjusted bya known temperature factor. JPT P. 1191