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Worldwide, hydrocarbon flow measurement is governed by regulations. It is well known in literature that CO2 strongly attenuates wave generated by ultrasonic flow meters, which is the technology most used in flare gas application. In this context, this work proposes and tests methodologies to mitigate ultrasonic flow measurement failures due to sign...
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... am thankful to Professor Márcio Martins for lending important equipment to this work and to Professor Márcio Coelho for the relevant discussions throughout the project. Figure 28 -Wind tunnel supervisory system screen ............................................................. 70 Figure 58 -Carbon dioxide effect on flow rate measurement considering assembly in recovery angle on transducers from Channel 1 ................................................................................ 119 Table 8 ...
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... operation with ultrasonic waves means transmitting acoustic energy from one medium to another [13]. In this context, it is important to understand the reflection and transmission process of an infinite ultrasonic wave, as shown in Figure 2. However, wave propagation is influenced by any boundary surface. ...
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... measurement model assumed here is based on the study by Matson et al. [2], as shown in Figure 23. Taking advantage of piezoelectric properties, voltage at VA level is supplied to Transducer A, which produces acoustic waves at ultrasonic frequency in a gaseous medium. ...
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... values for attenuation readings using ultrasonic flow meter is the empiric model [23] based on data for binary mixtures of N2 and CO2 [4], [27]. Measured attenuating coefficient is illustrated in Figure 24 and detailed in Table 5. The coefficient characterizes the attenuation, as explained at Chapter 2. Figure 24 and Table 5 analysis indicates that attenuation coefficient measured for pure air is 5787% higher than the estimated value by empiric model for 100% N2. ...
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... attenuating coefficient is illustrated in Figure 24 and detailed in Table 5. The coefficient characterizes the attenuation, as explained at Chapter 2. Figure 24 and Table 5 analysis indicates that attenuation coefficient measured for pure air is 5787% higher than the estimated value by empiric model for 100% N2. Although values of attenuation coefficient of dry air and N2 have found to be similar [32], the empiric model applied in this study do not consider air humidity. ...
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... wind tunnel is located at Research Group of Oleo & Gas Flow and Measurement (NEMOG, in Portuguese), at Federal University of Espírito Santo (UFES). The wind tunnel, as shown in Figure 25, is especially designed to test flow metering technologies for flare gas applications at high speed flows and high carbon dioxide concentration. The wind tunnel consists of a set of plastic polypropylene tubes with different spool tube sections lengths, presenting nominal internal diameter of 12 inches (290.5 mm). ...
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... "closed-circuit assembly" as illustrated in Figure 25. In this configuration, the flow rate is recirculated, enabling the evaluation of the ultrasonic flow meter after gas injection. ...
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... such configuration the ultrasonic flow meter is evaluated at several flow rate levels. This setup is especially suitable for establishing a turbulent and fully developed velocity profile at the test section, since it is a curve free configuration, as shown in Figure 26. Considering typical offshore flare gas operational conditions [83], the hydrodynamic similarity matches between NEMOG's wind tunnel flow and typical offshore flare gas flow [84], [85]. ...
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... experiment controlling, instrumentation, monitoring, as well as data acquisition are automated by a supervisory system based in LabView [86] platform. Figure 28 shows one supervisory system screen, indicating some monitored variables. The flow rate is regulated in the supervisory system, which allows operation in open loop control or closed loop control. ...
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... connection for carbon dioxide injection in the wind tunnel is located in the upper horizontal segment, as detailed in the P&ID diagram in Figure 27. The gas cylinder is connected to a ball valve, which is installed in the pipe connection by a silicone hose. ...
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... LDA hardware setup consists of: i) Transmission system of the Solid-State Laser; ii) Receiving unit for the light signal scattered by the tracking particle and iii) Signal processor. Figure 29 illustrates LDA sketch, as installed at wind tunnel. ...
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... tracer particles injector is placed at 10.5 meters (36.2D) upstream to the LDA measuring section. Particles injection and LDA mounting in NEMOG's wind tunnel are shown in the P&ID diagram at Figure 27. ...
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... the flow velocity is measured at selected discrete point along the transversal section. The motion of the LDA transmission unit is provided by an automated unidimensional traverser, as indicated in Figure 29. ...
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... the difference between temperature of the gas flow TIT T and environmental temperature RT T , is calculated as Equation (5.8). Results are shown in Figure 32. Since both local atmospheric air and carbon dioxide are working fluids, it is necessary to estimate density and viscosity considering temperature, pressure and gas composition. ...
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... experimental design results in a total of 2 3 = 8 experiments or 8 treatment combination. Geometrically, this design is represented by a cube, in which each corner represents a test run, as Figure 42(a). ...
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In this work we combine a multipath ultrasonic gas flow meter (UFM) with an ultrasonic air-coupled phased-array. This allows complementing the advantages of a multipath UFM, i.e. higher accuracy and more robustness to irregular flow, with the extended velocity measuring range due to sound drift compensation via a phased-array. We created a 3D-print...
Citations
... This attenuation may cause an ultrasonic meter to lose the signal passing between its transmitters and receivers. The effect is more significant at low pressure [32]. A reduction in the ultrasound signal strength will impact the measurement resolution and may have a detrimental effect on accuracy. ...
Carbon Capture, Utilisation and Storage (CCUS) is a key element in the United Kingdom Government strategy for reducing carbon dioxide (CO2) emissions. The UK aims to capture and store 10 million tonnes of CO2 each year by 2030.
At each stage in the CCUS infrastructure, accurate measurement of the CO2 flow rate is required, over a range of temperatures, pressures, flow rates and fluid phases, where the flow measurement must be validated through a credible traceability chain. The traceability chain provides the underpinning confidence required to verify meter performance, financial and fiscal transactions, and environmental compliance. The UK equivalent of the EU Emissions Trading System (EU ETS) specifies a maximum uncertainty value for CO2 flow measurement. Accordingly, the provision of accurate and traceable flow measurement of CO2 is a prerequisite for an operational CCUS scheme.
However, there are currently no CO2 flow measurement facilities, nationally or internationally, providing traceable flow calibrations of gas phase, liquid/dense phase and supercritical phase CO2 that replicate real-world CCUS conditions. This lack of traceable CO2 gas and liquid flow measurement facilities and associated flow measurement standards is a significant barrier to the successful implementation of CCUS projects worldwide.
This paper presents an overview of the traceability chain required for CO2 flow measurement in the UK and globally. Current challenges are described along with potential solutions and opportunities for the flow measurement community.
... This attenuation may cause an ultrasonic meter to lose the signal passing between its transmitters and receivers. The effect is more significant at low pressure [32]. A reduction in the ultrasound signal strength will impact the measurement resolution and may have a detrimental effect on accuracy. ...
... Among these research centers, the Research Group for Oil and Gas Flow and Measurement (NEMOG, in Portuguese) stands out, addressing many issues found in the industry, with a focus on the petrochemical industry. The lab's facilities, which according to Franco and Ramos (2021) are all fully instrumented and automated (due to academic and safety reasons), carry out research on flare gas flow measurements ), Franco (2020), water-in-oil emulsions, three-phase flow in pipes (oil, air, and water), and two-phase (air and water) flow. ...
The flow of a two-phase mixture is a complex phenomenon. One reason is that interactions between phases depend on variations in operating conditions (velocity of the phases, pressure, tube geometry, etc). These operating conditions impose the formation of different flow patterns that can undergo pattern transition depending on the change in geometric cross-section. This work proposes a mechanistic model for any tube inclination from horizontal to near-vertical and considers the concentric annulus condition as a particular case of a pipe. Mathematical relationships are developed to calculate shear stresses and velocity profiles in an annulus under different inclinations. Based on geometric parameters, a new methodology helps obtain the wetted area and perimeter of the liquid and gas phase. Furthermore, two scenarios are considered to verify the model's reliability: horizontal piping and vertical piping, and good performance was found in both scenarios. Finally, a generalized air-water flow pattern map based on dimensionless groups is obtained. Furthermore, the influence of the inner tube on the stratified liquid level is studied, and it is found that the insertion of the inner tube causes an increase in the liquid level as the superficial gas velocity increases. Also, the influence of the tube inclination in the following transitions between flow patterns is verified: smooth stratified/wavy stratified, wavy stratified/annular dispersed liquid, stratified/intermittent, annular dispersed/intermittent, and intermittent/dispersed bubble. Regardless of the direction, the intermittent flow pattern is the most affected, increasing its area as the inclination increases if the flow is upward and decreasing its area as the inclination increases if the flow is downward.
... Comparando a atenuação em componentes do gás natural, o dióxido de carbono (CO2) é cerca 4 vezes mais atenuante que o metano (CH4) (Ejakov et al., 2003). Isso explica a ocorrência de falhas em medidores de vazão ultrassônicos operando em escoamentos com elevada concentração de CO2 (Barros & Ramos, 2016;Franco, 2020). ...
Pre-salt natural gas presents high carbon dioxide (CO2) concentration, introducing new challenges for offshore flare gas
flow measurement. CO2 affects the propagation of waves emitted by ultrasonic flow meters due to typical molecular
attenuation of CO2, resulting in failures of flow measured. Such signal attenuation intensified by high flow velocities,
characteristic of blow up events or compressor stops. This work proposes and experimentally analyze methodologies for
identification and mitigation of fail in transit time ultrasonic flow meters operating in high CO2 and high flow velocity.
Analyzes indicate that the methodology employed can increase the limit CO2 concentration, without reading failure from
46% to 100% of CO2, depending on transducers installation.
