Fluid Transfer Lines Research Articles

Experimental investigation of valve driven transient effect in liquid nitrogen pipeline

Liquified cryogenic fluids like Liquid oxygen, nitrogen, and hydrogen have various industrial applications. The cryogenic fluid transfer lines are generally fitted with valves to regulate, and control flow. The sudden operations of these valves lead to transient effects characterized by pressure fluctuations. The severity of pressure oscillations depends on various parameters including the valve parameters and the fluid properties. The fluid properties of cryogenic fluid in turn vary rapidly during such valve transients. In this work, a Cryogenic test facility is developed to investigate the valve-driven transients in a liquid nitrogen pipeline. The effect of the transient in the system is evaluated for two different cases of tank pressure and flow rate. The behavior of the transient is detected with the help of dynamic pressure sensors and RTD sensors. Further, the results are interpreted to understand the effect of the transient in the cryogenic fluid transfer system.

Prediction of foreign material contamination in fluid transfer lines using outlier detection method

Filters are often used in beverage and other production lines to remove foreign material during fluid transfer. The removal of foreign material causes clogging, which leads to further generation of foreign material due to an increase in the mesh opening or damage to the mesh. Although clogging can be determined from flow rate and pressure changes, it is difficult to detect clogging until after the event has progressed to a certain degree, during which time foreign material is generated. In this study, we extracted feature values from the differential pressure applied to the filter and performed machine learning using One-Class SVM to predict foreign material contamination in advance. We applied this method to an actual fluid transfer line and confirmed its usefulness.

Performance Comparison of CPC based solar installations at different locations in India and analysis of variation pattern

Currently the industrial heat demand is met by using expensive fossil fuels. Exclusive use of solar energy is not feasible due to the fluctuating pattern of solar radiation intensity. Solar hybridization with the existing heating system can be an appropriate solution to meet the process heat requirement of many industries. Concentrator Solar Thermal (CST) technologies can generate the medium temperature heat required for industrial processes. The present study was undertaken with an objective of comparing and analyzing the designed performance of the solar fields using the Compound Parabolic Concentrator (CPC) technology against the actual measured performance values for boiler feed water preheating application at two different locations in India. The optical efficiency of the CPC collector, 64.8%, obtained when tested as per part 5 of IS 16648:2017 was used for designing the solar fields as per the daily heat requirement. The performance of the installations at both the locations was monitored for a period of five months. The observed variation in the performance of each installation than the designed performance was compared and analyzed for the causes. The average variation in designed and measured performance was in the range of 9.0% to 9.8% for location 1 and 2 respectively, attributing to heat rejection from the collector attachments and fluid transfer lines, dust effect on the absorber and reflector of CPC, instrument’s uncertainty, other losses due to shadow effect, vacuum loss from the tubes, dislocation of tubes, heat removal and usage pattern etc. The reasons of the losses from both the fields were of the similar nature, which should be taken into account to design a solar thermal system to achieve predicted performance near to the designed performance. Preheating of boiler feed water is one of the potential applications of solar CPC technology.

Estimation of pressure drop of single-phase flow in horizontal long pipes using artificial neural network

Large- pressure drop and drag along the pipe route is one of the problems with fluid transfer lines. For many years, various methods have been employed to reduce the drag in fluid transmission lines. One of the best ways for this purpose is reducing friction coefficients by utilizing drag lowering materials. Experimentally by adding minimal amounts of this material at the ppm scale to the lines and reducing the drag of the flow, fluid can be pumped without the need to change the size of the pipe. In this study, the effect of carboxymethylcellulose biopolymer on the water flow reduction in a 12.7- and 25.4-mm galvanized pipe was investigated. In order to have a comprehensive analysis of process conditions, experiments were carried out with three different levels of concentrations, flow rate and temperature. Also, as a new innovation in this investigation, the outputs of the experimental data were evaluated and analyzed using the Taguchi method and neural network system, and optimized through a genetic algorithm. In this study, the highest rate of drag reduction will be achieved at 39 ° C and at a concentration of 991.6 ppm and flow rate of 1441.1L/h was 59.83% at 12.7-mm diameter.

Numerical assessment of the global performance of spar and FPSO connected by horizontal pipeline bundle

The global performance of a Spar and FPSO (floating production storage and offloading) connected by horizontal fluid transfer lines (FTLs) bundled with a large carrier pipe, called GAP (gravity actuated pipeline), is evaluated by using a fully coupled multi-body-mooring-riser time-domain analysis program. The horizontal pipeline bundle is attached to a carrier pipe to give sufficient bending stiffness and make the system neutrally buoyant. The pipeline bundle is supported by chains attached to Spar at one end and to FPSO at the other end allowing the movement mainly in the axial direction. The FPSO is to weathervane with respect to a bow external turret. The hydrodynamic coefficients are obtained from multi-body diffraction/radiation 3D panel program in the frequency domain and they are subsequently used in the time-domain simulation program to carry out the fully coupled time-domain global motion analysis. The moorings and risers attached to the FPSO and Spar are modeled with high-order finite elements (FEs). The pipeline bundle is also modeled with finite elements as one line member with the equivalent diameter and structural properties. The axial friction forces as well as the transverse drags on the pipeline bundle are considered because their accumulated effects along the very long FTL can be significant. The coupled relative motions of the Spar and FPSO can significantly affect the dynamics and tensions of the FTL. The dynamics of the FTL can also affect the relative motions of the two platforms too. The complex coupled system is also significantly affected by the headings of environmental loadings.

Gas Composition Monitoring in Cryogenic Fluid Transfer Lines

A range of aerospace applications require chemical sensing technology [1]. One application area is the monitoring of fuel leaks in launch vehicles. Detection of low concentrations of hydrogen and hydrocarbon fuels is critical in avoiding explosive conditions that could harm personnel and damage the vehicle. Reliable vehicle operation also depends on the timely and accurate measurement of these leaks. Further, the simultaneous measurement of oxygen as well is an important component determining if a hazardous condition exists. Detection of low concentrations of fuel, such as hydrogen or methane, is generally necessary from room temperature to cryogenic ambient, and in air or inert gas atmospheres. Thus, the development of multiple sensors (a sensor array) to determine the concentration of fuels, such as hydrogen, hydrocarbons, oxygen, and other parameters is necessary for aerospace applications. Development of Smart Sensor Systems for the detection of leaks has been on-going [1-2]. This work is based on the ability to produce microsensor platforms that can be tailored to measure a range of species. Combined with that effort has been the development of miniaturized hardware and software systems (“Lick and Stick” technology) that can be implemented in aerospace applications. These “Lick and Stick” systems include signal conditioning, data processing, power, and communication in a compact structure, for placement in multiple locations to improve the awareness of an environment. Figure 1a) shows an example this technology: a “Lick and Stick” system composed of a hydrogen, hydrocarbon, and oxygen sensor systems with a microprocessor and communication capabilities. Other sensors such as pressure and humidity can be included. Each sensor is integrated with its own temperature detector and heater for temperature control facilitated by the Smart Sensor electronics. This paper describes the extension of this Smart System leak sensor technology to the monitoring of the gas concentrations in cryogenic fluid transfer lines. In particular, cryogenic fluid transfer lines that carry liquid hydrogen to a launch vehicle are often purged with helium before the lines are exposed to the ambient. This is done in order to insure that residual hydrogen concentrations within the transfer lines are below hazardous levels before the introduction of oxygen. Pure helium is used, in contrast to, for example, nitrogen, to ensure the purge gas itself does not liquefy. Given rising costs of helium, there is a desire to minimize its use to that least amount needed in order to establish a nonhazardous level of hydrogen within the cryogenic fluid transfer line. One method to reduce helium usage is to monitor the hydrogen concentration within the cryogenic fluid transfer line and measure when nonhazdarous concentrations are achieved. This implies that a gas monitoring be mounted in contact with the interior of the cryogenic fluid transfer line and be able to withstand cryogenic temperatures. Measurements of interest include hydrogen and oxygen, but also pressure and humidity. A cryogenic fluid transfer line gas monitoring system based on chemical microsensors is under development to address this application. The core technology is based on the “Lick and Stick” sensor system of Figure 1a), but major modifications are necessary for this application. A prototype systems is shown in Figure 1b). The sensor elements, such as hydrogen, oxygen, and humidity sensors, are packaged for insertion directly into the cryogenic flow line using the fittings shown. These sensor elements do not need to operate at cryogenic temperatures, but must at least survive exposure to these conditions; sensor operation occurs later during the purge of the fluid transfer line at low temperatures closer to ambient after the cryogen flow. The sensor elements are remotely connected to the Smart Sensor electronics, which operate at ambient conditions. This paper describes the development of this prototype cryogenic fluid transfer line gas monitoring system, its initial testing, and comparison of results to reference instruments. It is concluded that the use of microsensors for this application have the potential to provide real-time monitoring capabilities in applications such as cryogenic fluid transfer lines, and thus provide a method to monitor and minimize the use of helium in such applications.

Kizomba A and B: Installation Overview

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 17941, "Kizomba A and B: Installation Overview," by J.B. Bates, G.O. Gernon, and M.D.A. Gillette, ExxonMobil, prepared for the 2006 Offshore Technology Conference, Houston, 1-4 May. Completing the Kizomba A and B projects with world-class schedule performance was a rare opportunity that yielded outstanding results. These two projects, within 7 miles of each other in Block 15 offshore Angola, were brought on line 11 months apart. Kizomba B built upon experience gained from Kizomba A to improve performance from contract award to the start of production. Continuous implementation of lessons learned and repeat use of Kizomba A prime contractors and ExxonMobil personnel resulted in time savings and installation-activities flexibility that ultimately contributed to an improved first-oil date for Kizomba B. Introduction Kizomba A and B shared the same field-development concept that included subsea drill centers and a close-moored surface wellhead platform (SWHP) tied back to a spread-moored floating production, storage, and offloading vessel (FPSO). The FPSO and SWHP are connected by flexible fluid-transfer lines. Oil is offloaded from the FPSO by use of a buoy-based oil-offloading system (OOS) composed of one oil-offloading buoy (OOB), its mooring system, and two 20-in. rigid steel-pipe oil-offloading lines (OOLs). Figs. 1 and 2 illustrate the similar Kizomba A and B field-development concepts. Execution Strategy Execution strategy, which was consistent between the two projects, specified four engineering, procurement, and construction (EPC) subprojects awarded to four prime contractors, and separate contracts for a mobile offshore drilling unit (MODU) and a main instrumentation and controls contractor. Tieback Subprojects Unlike the other Kizomba B subprojects, the tiebacks-subproject deliverables and installation activities differed significantly from those of Kizomba A. Table 1 in the full-length paper describes the work scope of both subprojects. The differences necessitated changes in established procedures, some new procedures, and modified installation equipment in certain instances. Most components of the Kizomba B tiebacks subproject required significant changes from Kizomba A, including the following.The SWHP tieback system had different fluid and flow requirements, which necessitated different flexible pipes and a different supplier.The subsea tieback system required longer flowlines, and addition of production flowlines from the remote drill centers to the FPSO required insulated pipe-in-pipe (PIP) flowlines and risers and insulated jumpers.Subsea hardware was significantly different.The FPSO mooring system had fewer lines and different installation procedures. Personnel One aspect of the tiebacks subproject that closely followed the "Design One, Build-Multiple" philosophy was the effort to retain the same design, procurement, and installation personnel from Kizomba A to B from both operator and contractor. The same offshore organization accompanied the main installation vessel, the field-development ship (FDS), for both Kizomba A and B. However, the overall project execution timelines overlapped for several months, causing the contractor to use two separate lead-project management staffs to direct each project, ensuring that priori-ties for each were managed effectively.

New Subsea Technology Aims To Cut Well-Intervention Costs

Deepwater subsea well intervention must be done with mobile offshore drilling units (MODUs), which can be very expensive. The cost per intervention using the standard MODU averages up to U.S.$10 million, in addition to the lost or deferred production. With deepwater production poised to play an even greater role in meeting global hydrocarbons demand, those costs will become increasingly burdensome. A new technology unveiled by ExxonMobil promises to mitigate this costly expense and significantly reduce the cost and time of downhole logging, acidizing, and other interventions in deepwater oil and gas wells. The subsea-intervention-module (SIM) technology offers a riserless way to deploy a seafloor coiled-tubing (CT) unit from a specially designed support vessel. ExxonMobil says the new technology, which it has been working on for the past 4 years, is advanced well beyond concept stage and has undergone significant high-risk engineering and component testing. The technology is now entering the detailed design and construction phase, and it will undergo further development to complete its design and its integration with subsea facilities. The SIM system—compromising a subsea CT system and a purpose-built monohull vessel that provides deployment, control, and support—is designed for use in 2,000 to 6,500 ft of water and can be used in even deeper subsea production interventions. It will be able to accommodate well depth of up to 13,000 ft below the seafloor. The system can be used for intervention on any subsea well constructed with 36-in. structural casing and completed with a horizontal tree. First use of the technology will be offshore west Africa in 2008. To commercialize the technology, ExxonMobil has licensed the SIM system to a joint venture between BJ Services Co. and Otto Candies LLC. The venture will operate the SIM system following the completion of design and construction. SIM Support Vessel The SIM system consists of the vessel—consisting of a dynamically positioned vessel, compensated deployment system, and controls—and the tool, which includes the CT module, blowout-preventer (BOP) module, one-way fluid-transfer lines, and remotely operated vehicle (ROV) with power and control umbilical. The SIM support vessel is a monohull vessel with double skin, a large working moonpool, and diesel/electric propulsion with a dynamic-positioning system. The vessel is the mother ship for the subsea CT unit. The self-supporting vessel carries stores and supplies for a 30-day period to support multiple well-intervention missions and can be replenished at sea if needed. The vessel also contains a helicopter deck and mooring facilities on both sides for a supply vessel. The vessel is 372 ft long and 79 ft wide, with an 18-ft draft (Fig. 1). It can accommodate up to 97 people and operate in up to 6,500 ft of water depth. The moonpool is 43×36 ft and located in the middle of the vessel, with a 750-ton, single-wire Huisman deployment system above. The vessel also includes deployment capability of two ROVs. A state-of-the-art control room includes the SIM control station, two ROV control stations, and a system to control and monitor CT operations and deployment.