Two flow loops are currently operated by TUSTP. One is a two-phase gas-liquid loop and the other is three-phase gas/oil/water loop. Following is a brief description of both loops.
Two-Phase Flow Loop
This flow loop is an outdoor 2-inch loop operated with an air/water system. The loop flow capacity is 1500 bbl/d liquid and 250,000 scfm of gas at 120 psig. It consists of a metering section to measure the single-phase gas and liquid flow rates, and five test sections, with different compact separators, as described below.
The gas flow rate into the loop is controlled by a regulating valve and metered utilizing either a MicromotionŽ mass flow meter or a DanielŽ orifice flow meter. The liquid phase is supplied from a 400-gallon storage tank at atmospheric pressure, and pumped to the liquid feeder line with a centrifugal pump. Similar to the gas phase, the liquid flow rate is controlled by a regulating valve and metered using orifice or mass flow meters. The single-phase gas and liquid streams are combined at the mixing tee. The two-phase mixture downstream of the test section is separated utilizing a conventional separator. The gas is vented to the atmosphere and the liquid is returned to the storage tank to complete the cycle.
Test Sections Available for Two-Phase Flow Loop
Currently, ten different test sections are in operation in the two flow loops. Six are attached to the outdoor gas-liquid loop, as listed below:
- Hydrodynamic GLCC Test Section
This is a 3-inch 8-ft dual-inlet GLCC equipped with a liquid trap on the gas leg to measure liquid-carry-over, and gas trap on the liquid leg to measure gas carry-under. Ports are also available along the GLCC for conducting local velocity and pressure measurements. - Control GLCC Test Section
This is a single-inlet 3-inch 8-ft GLCC equipped with innovative, state-of-the-art Fisher FloVue Final Control System on the gas leg and on the liquid leg. The system combines the 9000 System actuator, a FIELDVUE digital valve controller and Design PC control valve. The control system is implemented using a LabView Control Kit. The facility enables experimental testing and verification of several control strategies (see linked figure) including feed forward and feedback. - Helical Pipe Test Section
This facility aims at studying slug dissipation/flow conditioning is shown in the linked figure. It consists of a 2-inch flexible transparent pipe coiled in a helical shape. The helical pipe can be coiled in different diameters from 0.74m to 1.95m as well as different helical pitch angles. Slug dissipation is measured by conductance probes located in every turn of the helix. A slug generator is also attached to the facility. - Predictive Control Test Section
This section is connected to the control GLCC facility. The section includes a pair of conductance probes to detect slugging conditions. The output of the probes is interfaced with the control system of the GLCC. Slugs of different lengths generated by a slug generator, pass through the detection section and flow into the control GLCC. This facility allows testing of feed forward control strategies. - Slug Damper Test Section
This is another flow conditioning system aimed at dissipating slugs upstream of the GLCC inlet. As shown in the linked figure, it consists of dual 3-inch, schedule 80, clear PVC pipes, equipped with a segmented orifice, located in the lower liquid leg. The liquid slugs (generated by the slug generator) are blocked by the orifice and accumulated in the lower leg, while the gas passes through the upper gas leg into the GLCC. This dampens the slug and provides a smooth liquid flow rate through the orifice into the following GLCC. - GLCC for High GOR – Wet Gas Applications Test Section
GLCC can be used as a wet gas scrubber to knock out the liquid droplets by modifying its configuration. For such application, it is crucial to understand the separation mechanism and the GLCC performance for high gas velocity and then improve the design criteria. The objectives of this study are to design a new GLCC with a specific design of a liquid film trap, (see linked figure) conduct experimental investigation and develop mathematical model. The experimental investigations are conducted to evaluate the improvement of operational envelope and the percentage liquid carryover. Mechanistic models are being developed for characterizing upward swirling flow above the inlet of the GLCC and the droplet size that can be separated for the gas core, which is used to predict the separation efficiency.
Three-Phase Flow Loop
This indoor, fully instrumented, state-of-the-art, two-inch gas/oil/water flow loop was constructed as part of the 5-year U.S. Department of Energy (DOE) project granted to TUSTP. The facility, shown in the linked figure, enables year-round data acquisition and simultaneous testing of different compact separation equipment. A technical grade white mineral oil type Tufflo® 6016 with a specific gravity of 0.857 is used as the experimental fluid along with tap water and air.
The loop consists of a metering and storage section and a modular test section. The metering and storage section includes air compressor, water and oil storage tanks, pumps, Micromotion® mass flow meters and a downstream three-phase conventional separator. The modular test section consists of four test stations. This flexibility enables the testing of single separation equipment, such as compact separators or conventional separators, or any combination of this equipment, in parallel or series, forming a compact separation system configuration. Control valves placed along the flow loop control the flow into and out of the test sections. The flow loop is also equipped with several temperature sensors and pressure transducers for measurement of the in-situ pressure and temperature conditions. All output signals from the sensors, transducers and metering devices are collected at a central panel. A state-of-the art data acquisition system, built using LabView® software, is used to both control the loop and acquire data.
Test Sections Available for Three-Phase Flow Loop
In the indoor three-phase flow loop, four test sections are available. These are briefly described below.
- Hydrodynamic LLCC Test Section
This is a 2-inch I.D. 80-inch tall facility, as shown in the linked figure. The oil-water mixture flows into the LLCC through a 25-degree downward inclined tangential inlet of 2-inch ID, located 44 inch below the top of the LLCC. The mixture is split into two streams, the oil overflow stream and the water underflow stream. The flow rate in each stream is controlled manually using the two valves located downstream of the LLCC. The flow rates and water cuts are measured with several Micromotion mass flow meters. - GLLCC Test Section
The GLLCC, shown in the linked figure, is a 3-inch 8-ft pipe, similar to the GLCC, but used for separating gas/oil/water flow. It has three outlets: The gas is removed from the top, while the oil and the water mixture flows to the bottom. Due to the centrifugal forces, the oil moves to the center. A special 1-inch oil finder is provided at the center of the GLLLC to remove the oil, while the water is removed tangentially from the bottom. The flow and water cut measurements and the control of the flow in the different streams are done in a similar manner used for the LLCC. - LLHC Test Section
This facility includes a Modular Production Equipment/NATCO 2-inch Hydro-swirl hydrocyclone as shown in the linked figure. Particle size distribution upstream of the LHC will be analyzed using a CILA analyzer capable of measure particles from 0 to 192 mm. The sample will be taken using an iso-kinetic sampler, and a surfactant will be added to the sample in order to keep the particle size distribution constant during the analysis. - Horizontal Pipe Separator (HPS) Test Section
The HPS is based on a simple concept, in which a horizontal pipe spool with appropriate geometry promoting the natural separation of the phases is utilized. Optimal design of the pipe separators can replace vessel separators, decreasing costs and simplifying installation and operation. It could be very effective for separating oil dominated flows. As shown in the linked figure, it consists of a 4-inch horizontal pipe section, equipped with mass flow meters located upstream and downstream. The oil-water flow into the HPS is mixed at a mixing-T and a static mixer. The inlet and the outlet pipes are 2 inch in diameter. Experiments are conducted to develop mechanistic model by measuring the liquid level, droplet size distribution and evaluating the separation efficiency at stratified flow conditions.
