关 键 词：

机械类毕业论文中英文对照文献翻译 机械类 毕业论文 中英文 对照 文献 翻译 紧凑型 柱状 旋流分离器 技术 目前 发展 状况

资源描述：

【机械类毕业论文中英文对照文献翻译】紧凑型管柱状气液旋流分离器技术目前的发展状况,机械类毕业论文中英文对照文献翻译,机械类,毕业论文,中英文,对照,文献,翻译,紧凑型,柱状,旋流分离器,技术,目前,发展,状况

内容简介：

D I S T I N G U I S H E D A U T H O R S E R I E S58JULY 1998 STATE OF THE ART OF GAS/LIQUIDCYLINDRICAL-CYCLONECOMPACT-SEPARATOR TECHNOLOGYOvadia Shoham, SPE, U. of Tulsa, and Gene E. Kouba, SPE, Chevron Petroleum Technology Co.SUMMARYThe petroleum industry has relied mainly on conventional, vessel-type separators to process wellhead production of oil/water/gasflow. However, economic and operational pressures continue toforce the industry to seek less expensive and more efficient separa-tion alternatives in the form of compact separators, especially foroffshore applications. Compared with vessel-type separators, com-pact separators, such as the gas/liquid cylindrical cyclone (GLCC),are simple, low-cost, low-weight separators that require little main-tenance and are easy to install and operate. However, the inabilityto predict GLCC performance adequately has inhibited its wide-spread deployment. Current R&D is aimed at creating the neces-sary performance-prediction tools for proper design and operationof GLCC separators. This paper presents the status of the develop-ment of the GLCC, the state of the art with respect to its simulationand design, and current successful and potential applications. INTRODUCTIONThe GLCC (Fig. 1) consists of a vertical pipe with a tangentialinclined inlet and outlets for gas and liquid. The tangential flowfrom the inlet to the body of the GLCC creates a swirl that producescentrifugal and buoyancy forces on the fluids that are an order ofmagnitude higher than the force of gravity. The combination ofgravitational, centrifugal, and buoyancy forces separates the gasand liquid. The liquid is pushed radially outward and downwardtoward the liquid exit, while the gas is driven inward and upwardtoward the gas outlet. The low-cost, low-weight, compact GLCCseparator offers an attractive alternative to the conventional vessel-type separator. A size comparison between the GLCC and conven-tional vessel-type vertical and horizontal separators has been con-ducted recently for a typical field application with oil and gas flowrates of 100,000 B/D and 70,000 Mscf/D, respectively, at 100 psig.1For this case, the required GLCC inner diameter and height are 5and 20 ft, respectively. These dimensions are approximately one-half of the corresponding dimensions of the required conventionalvertical separator (9x35 ft) and about one-quarter of the dimen-sions of a conventional horizontal separator (19x75 ft). The operational envelope of a GLCC is defined by two limitingphenomena: liquid carry-over in the gas stream and gas carry-underin the liquid stream. The onset of liquid carry-over is identified by thefirst trace of liquid in the gas stream. Similarly, the first observablebubbles in the liquid underflow mark the onset of gas carry-under.The difficulty in developing accurate performance predictionsarises largely from the variety of complex flow patterns that canoccur in the GLCC. The flow patterns above the inlet can includebubble, slug, churn, mist, and liquid ribbon. Below the inlet, theflow generally consists of a liquid vortex with a gas-core filament.At liquid levels far below the inlet, the liquid flows from the inletto the vortex in a swirling film.This difficulty in predicting the hydrodynamic performance ofthe GLCC has been the single largest obstruction to broader use ofthe GLCC. Even without tried and tested performance predictions,several successful applications of GLCCs have been reported.2Thedevelopment of reliable performance-prediction tools will improveGLCCs through hardware modifications and, ultimately, will gov-ern the speed and extent to which GLCC technology is deployed inexisting and new field applications. HARDWARE DEVELOPMENTSFew systematic studies of design configurations of different GLCCmechanical features have been conducted. Recent laboratory obser-vations and computer simulations indicate that hardware modifica-tions to the GLCC can have a profound effect on GLCC perfor-mance. Ref. 3 discusses these in some detail. The following is a sum-mary and update of the most important hardware improvements.Inlet Design. The inlet section determines the incoming gas/liq-uid distribution and the initial tangential-inlet velocity in theGLCC. Because GLCC performance is strongly dependent on thetangential-inlet velocity, the inlet has been the single mostredesigned component of the GLCC.Inclined Inlet. Conventional vertical separators typically use aperpendicular inlet. Recent studies on the GLCC have demonstrat-ed that an inclined inlet improves GLCC performance by reducingliquid carry-over in the gas stream through two mechanisms.4First, the downward inclination of the inlet promotes stratificationand provides preliminary separation at the inlet nozzle. Second, thedownward inclination causes the liquid stream to spiral below theinlet after one revolution, preventing the liquid from blocking theflow of gas into the upper part of the GLCC.Inlet Nozzle.The nozzle is the last element of the inlet that influ-ences flow distribution and the tangential velocity entering theGLCC body. The tangential inlet nozzle is the most expensive part ofthe GLCC to fabricate. Several nozzle configurations have been test-ed, aimed at optimizing hydrodynamic performance cost-effectively.The optimum configuration for hydrodynamic performance is a thin,rectangular tangential wall slot, which is difficult to fabricate. On theother hand, the concentric-circular tangential inlet is easy to fabricatebut exhibits lower performance. A preliminary experimental com-parison of three different inlet-slot configurations (rectangular, con-centric-circular, and crescent) with the same cross-sectional areafound that the concentric-circular nozzle (reduced pipe) configura-Copyright 1998 Society of Petroleum EngineersThis is paper SPE 39600. Distinguished Author Series articles are general, descriptive repre-sentations that summarize the state of the art in an area of technology by describing recentdevelopments for readers who are not specialists in the topics discussed. Written by individu-als recognized as experts in the area, these articles provide key references to more definitivework and present specific details only to illustrate the technology. Purpose: to inform the gen-eral readership of recent advances in various areas of petroleum engineering. A softboundanthology, SPE Distinguished Author Series: Dec. 1981Dec. 1983, is available from SPEsCustomer Service Dept. JULY 199859tion had the poorest performance, while the crescent nozzle (tan-gential flat plate) performed closest to the rectangular slot.5Dual Inlet. Dual inclined inlets provide preseparation of the inletstream into a liquid-rich stream (lower inlet) and gas-rich stream(upper inlet). Testing of the dual inlet indicated a significant improve-ment in liquid-carry-over performance at low to moderate gas rates(slug flow dissipating to stratified flow at the inlet) with less dis-cernible improvement at high gas rates (annular flow at the inlet).6GLCC-Body Configuration. Despite the simple design of theGLCC, several possible modifications to the body configurationcan influence performance. Inlet Location. For GLCCs without active liquid-level control, itis important to locate the inlet section just above the liquid level.Most testing to date indicates that the optimum liquid level in thesingle-inlet GLCC is approximately 1 to 3 L/d below the inlet.Liquid levels farther below the inlet than 3 L/d result in significantdecay in the tangential-inlet velocity, which compromises theGLCC performance. If the liquid level is above the inlet, gas mustblow through the liquid and is more likely to cause carry-over.Optimum Aspect Ratio. The aspect ratio is the ratio of GLCClength to diameter. The dimensions of the GLCC influence perfor-mance and cost. For a given diameter, the length of the GLCCabove the inlet provides liquid-surge capacity, while the lengthbelow the inlet determines residence time for separating bubblesfrom the liquid. In addition, centrifugal and buoyancy forces areinversely proportional to diameter and tangential-velocity decay isdirectly proportional to length. Because of the complexity of thisphenomenon, a fundamental set of criteria to determine optimumaspect ratio has been proposed only recently.1Cyclone-Body Taper.An investigation on diverging, converging, andcylindrical cyclones concluded that cylindrical walls are slightly supe-rior to either converging or diverging walls for gas/liquid separation.7Liquid-Level Controls. Active liquid-level control in a GLCC for awide range of flow conditions is not straightforward owing to itscompact size. Several different liquid-level-control strategies arebeing investigated, including flow control on the gas leg, flow con-trol on the liquid leg, and flow control on both legs. Also beingconsidered are combinations of backpressure control on the gas legand liquid-level control on the liquid leg. Other issues of concerninclude power requirements, robustness, and cost. Several alternatives for GLCC liquid-level control have beenimplemented. For example, a commercial multiphase measure-ment system has used conventional control equipment successful-ly to maintain a tight control on liquid level by controlling the gas-outflow rate of the GLCC. Another project explored low-poweralternatives to conventional level controls that exploit hydrostatic-head difference in the GLCC to operate the controls.8A recentstudy examined GLCC performance with a passive control systemthat uses only the flow energy and no external energy.5Crucial future work is to develop robust, active liquid-level-con-trol strategies. Because of the smaller residence time of the compactseparator and the stringent response time requirement of the controlvalve, this is not a simple extension of the control technology avail-able for large vessel-type separators. The strategies should enable theGLCC to handle slugging, surging, and a wide range of flow rates,from essentially full-gas-flow to full-liquid-flow conditions. Integrated Separation System. Great economic incentivesexist for the industry to move away from conventional gravity-based separators to compact separation systems. Depending onthe application, the GLCC can be used for full or partial sepa-ration. Partial gas separation allows downstream equipment tobe smaller (and therefore less expensive) and perform moreefficiently. The GLCC has been particularly effective whencombined with multiphase meters, desanders, and liquid/liquidhydrocyclones. Configured either alone or in combination withother equipment, the GLCC can reduce cost and weight signif-icantly. This is particularly important in designing or retro-fitting offshore platforms, where savings in platform-construc-tion costs may be many times greater than the cost of the sep-aration equipment. Fig. 1GLCC configuration.60JULY 1998 Another GLCC combination is two GLCCs used in series. A the-oretical work successfully predicted that a second-stage GLCC onthe gas leg would increase the liquid-carry-over performance of thetwo-stage GLCC to the onset of the mist-flow boundary, which wasanticipated as the theoretical performance limit.4It was found thatat very low liquid loading, the centrifugal forces on the liquidwould allow the operational envelope to push well beyond the fullydeveloped annular-mist-flow boundary. Acommercial measurement system has been developed that usesa second-stage horizontal pipe separator to remove any small gasbubbles that may have passed along with the liquid underflow fromthe GLCC. This has allowed extension of the system operationbeyond the “normal” operating range of the GLCC for completegas/liquid separation.Miscellaneous Hardware Improvements. Several other potentialimprovements have been considered; however, we have not dis-cussed them here because little or no performance information isavailable. These include a variable inlet-slot area and the config-urations of the gas and liquid outlets.SIMULATIONIn the past, performance predictions of GLCC separators havebeen carried out on the basis of experience, rules of thumb, andempirical correlations. These methods are limited in their abilityto be extrapolated to different flow conditions and untried appli-cations. Currently, efforts are under way to develop mechanisticmodels for the GLCC and conduct computational fluid dynamic(CFD) simulations. Mechanistic modeling offers a practical approach to GLCC designand performance prediction. Simplifying assumptions are used, but,ideally,the models still captureenough of the fundamental physics ofthe problem to allow interpolation and extrapolation to differentfluid-flow conditions. CFD simulations predict details of the com-plex hydrodynamic-flow behavior in the GLCC, including flow field,holdup distribution, and trajectories of discrete particles of the dis-persed phase. While well-suited for local simulation of single-phaseor dilute dispersion flows, current CFD simulators cannot yet handlethe complexities of the full range of multiphase flow. Furthermore,CFD models of large piping systems that include the GLCC typical-ly are too unwieldy to be practical for design purposes.Because mechanistic models are greatly simplified, they are notas detailed, rigorous, or accurate as CFD models. However, mech-anistic modeling has many advantages: speed of setup and compu-tation, ability to model an entire system, and suitability for PCoperation. Consequently, these models are more accessible to engi-neers as a design tool than are CFD models. Mechanistic Modeling. The ultimate aim of modeling work to datehas been to predict the operating envelope for the GLCC with respectto liquid carry-over in the gas stream and gas carry-under in the liquidstream. Each fluid-flow path has its own particular set of calculations.The starting point for either calculation path is the global distributionof gas and liquid in the GLCC, namely, the equilibrium liquid level. Equilibrium Liquid Level. The equilibrium liquid level in theGLCC is determined by the pressure drop between the gas and liq-uid outlets. Because the frictional losses in the GLCC are low, theequilibrium liquid level is a reasonable indication of the amount ofliquid in the GLCC. The model is based on a pressure balance onthe gas and liquid legs. Ref. 2 gives details of this model. Vortex Shape and Location. The shape and location of the vortexare important for prediction of both liquid carry-over and gas carry-under. The vortex model assumes rigid-body rotation (i.e., a lineartangential-velocity profile in the radial direction).2Coupling the cal-culations for equilibrium liquid level and vortex shape makes deter-mination of the location of the vortex and the height of the vortexcrown possible. This model of the global distribution of gas and liq-uid provides the groundwork for the performance models.Liquid Carry-Over. Liquid carry-over in the gas stream is largelydependent on the flow pattern in the upper part of the GLCC. Floodingmay occur in the GLCC at high liquid levels and low gas rates, produc-ing bubbly flow. The unstable liquid oscillations, characteristic of churnflow at moderate gas rates, may splash liquid into the gas outlet. Liquidcan also be carried out in droplets at the onset of annular mist flow athigh gas rates. At very high gas rates, the centrifugal force of the swirlinggas pushes the liquid to the wall of the pipe, where it may form anupward-spiraling continuous ribbon of liquid.At present, the onset of liquid carry-over is predicted for low tomoderately high gas rates. The key to onset of liquid carry-over hasbeen to predict accurately the maximum liquid holdup (volume frac-tion) occurring in the upper part of the GLCC under zero-net-liquid-flow conditions and its effect on the pressure balance between the gasand liquid legs. Fig. 2 compares model predictions with experimen-tal results in plots of the maximum liquid holdup in the upper GLCCregion (i.e., zero-net-liquid-flow holdup, yL0, vs. the superficial gasvelocity, vgs, in the GLCC).2Additional data collected for a range ofliquid viscosities from 1 to 10 cp showed negligible effect on thezero-net-liquid-flow holdup.6Once the maximum liquid holdupFig. 2Zero-net-liquid-flow holdup in air/water system.2Fig. 3Operational envelope for liquid carry-over in a 3-in.GLCC operated with air and water.2vgs, ft/secyL0vgs, ft/secvLs, ft/sec JULY 199861allowed in the upper part of the GLCC is known for a given gas rate,the pressure-balance calculation is used to determine the liquid raterequired to achieve this holdup and initiate liquid carry-over.Fig. 3 compares the experimental and predicted operationalenvelopes for a 3-in. laboratory GLCC in a loop configuration,operated with air and water at low pressures.2The operationalenvelopes are presented in terms of superficial liquid velocity, vLs,vs. superficial gas velocity, vgs, in the GLCC. The agreement ofmodel predictions with the data is very good. Comparison withdata from Ref. 6 showed that the model seems to capture the phys-ical phenomena and predict well the reduction of the operationalenvelope with increasing liquid viscosity.Future improvements to liquid-carry-over modeling will includeexpansion to different operational conditions (e.g., high gas rates)as well as prediction of the quantity of liquid carry-over anddynamic responses to flow-rate surges.Gas Carry-Under.Three mechanisms have been identified as possi-ble contributors to gas carry-under in the liquid stream: (1) shallowbubble trajectories prevent small bubbles from escaping to the gas-corefilament, (2) rotational-flow instability causes helical whipping andbreaking of the gas-core filament near the liquid exit, and (3) liquid-rate surges can produce a concentrated cloud of bubbles that hindersbubble migration to the gas core. Currently, attempts to predict gascarry-under have focused only on the first mechanism, discussed next.Bubble-Trajectory Analysis. This analysis is carried out byassuming successive steady-state force-balance calculations on abubble. The forces acting on the bubbles are centrifugal, buoyancy,and drag. Recent work compared bubble trajectories predicted bythe mechanistic model and CFD simulations for the same flow con-ditions.9Fig. 4, where x/d and r/R are the dimensionless axial andradial coordinates below the GLCC inlet, respectively, provides anexample of such a comparison. The figure shows good agreementwith respect to the trend and absolute value.Bubble-trajectory analysis10was used to predict the onset of gascarry-under and separation efficiency for different sized bubbles ina manner similar to the liquid/liquid analysis carried out for hydro-cyclones.11The minimum diameter of the bubble that alwaysmigrates from the GLCC wall to the gas core and thus is separated(i.e., d100) was predicted. Fig. 5 shows the effect of the ratio of thetangential velocity at the inlet slot to the axial velocity in the GLCC(namely, vtis/vz) on d100. The continuous line represents the regres-sion curve of the simulation results. For these conditions, d100decreases with increasing vtis/vzratio up to about 100 and remainsapproximately constant for larger values of this ratio.The region from the bottom of the vortex to the liquid exit iswhere small bubbles are separated and captured by the gas-core fil-ament. Because vortex height is a strong function of tangential-inletvelocity and bubble-trajectory length diminishes with vortexheight, an optimum tangential-inlet velocity must exist that mini-mizes gas carry-under. A tangential-inlet velocity that is too lowproduces insufficient centrifugal and buoyancy forces, whereas theavailable length for bubble trajectory is too short with a tangential-inlet velocity that is too high. As yet, a general scheme to determineoptimum velocity has not been presented.Work is now in progress to develop the methodology to predictoverall separation efficiency in a GLCC. This requires two addition-Fig. 4Bubble-trajectory comparison of mechanistic model andCFX simulations with vLs=0.25 ft/sec, vgs=10 ft/sec,vtis/vz=34, d=3 in., and db=20 m.9Fig. 5Effect of tangential-/axial-velocity ratio on d100for a 3-in.GLCC operated with air and water at atmospheric conditions.10vLs= 0.05 ft/secvLs= 0.1 ft/secvLs= 0.5 ft/sec100806040200d100, mvtis/vz62JULY 1998 al pieces of information: the amount of gas entrained and the bub-ble-size distribution. Coupling these to the bubble-capture efficien-cy ultimately will enable prediction of overall separation efficiency. CFD Simulation. Verifying mechanistic models with real data isnot always practical or possible. CFD simulations are used tovalidate and improve the mechanistic models. CFD simulationsfor the GLCC can be lumped into two broad categories: single-phase flow with particle tracking and two-phase flow. Single-Phase Flow and Particle Tracking. The simplest andmost widely used approximation for CFD simulation of two-phaseflow is to consider single-phase flow populated with particles (bub-bles) that neither interact with each other nor influence the flow.This, in effect, is simply solving for a single-phase-flow field andsuperimposing particle-trajectory tracking.CFD and bubble-trajectory analysis were used to investigate thesensitivity of gas separation to bubble-size distribution.12,13Two-and three-dimensional (2D and 3D) simulations14were carried outwith CFX, a commercially available CFD code.15The authors con-cluded that the axisymmetric simulations (2D) gave good resultscompared with the 3D simulations. Fig. 6 compares single-phaseCFD simulations with experimental data.16Both the data and CFDsimulations demonstrated that the tangential-velocity distributionis dominated by a forced vortex, confirming this assumption in themechanistic models. Furthermore, the CFD simulations also veri-fied the mechanistic model with respect to axial decay of tangen-tial-velocity distribution (5 to 7% L/d decay). The simulations in Ref. 14 also predicted the existence of anaxial-flow-reversal region where the flow is downward near the walland upward in the center core. The bubble-capture radius, Rcap, isdefined as the radial location where the axial-velocity component iszero as the flow reverses from downward to upward. Bubbles thatmigrate into the capture-radius area are separated and pushedupward into the upper part of the GLCC. Fig. 7 shows the captureradius as a function of the tangential-/axial-velocity ratio, vtis/vz,andaxial location below the inlet. The results indicate a rapid decline ofthe capture radius as the velocity ratio decreases below 10. The cap-tureradius and the reversal in the axial-velocity profile recently havebeen incorporated into the mechanistic model.9Two-Phase Flow. Actual two-phase-flow CFD simulation is still inits infancy. Such simulations should predict the influence of the dis-persed phase on the flow of the continuous phase and the interfacebetween the two phases. Recent two-phase-flow CFD simulationwork has proceeded on two fronts: with CFX14,17and throughdevelopment of a dedicated internal code.17The two-phase simula-tions provided details of the velocity field and gas-void-fraction dis-tribution. The simulations also provided the free interface betweenthe gas and liquid phases (vortex), which compared favorably withexperimental data. Fig. 8, which shows the gas-void-fraction distri-bution in the GLCC, gives an example of the results obtained. Thefigure reveals that the gas-void-fraction values at the top and bottomof the GLCC are nearly unity and nearly zero, respectively, indicat-ing efficient separation. For the first time, results have predicted thegas-core-filament diameter accurately and provided insight into themechanism for its formation (continuous entrainment and radialmigration of small gas bubbles into the gas core).*Fig. 6Axisymmetric-tangential-velocity prediction vs. data fora 7.5-in. GLCC operated with air and water at atmospheric con-ditions.14Fig. 7Variation of capture radius with tangential-/axial-veloci-ty ratio.14vtis/vzRcap/R6 in.12 in.Fig. 8Void-fraction distribution for a 7.5-in. GLCC operated withair and water at atmospheric conditions.14=0.98=0.00Vt, ft/sec*Unpublished results, F.M. Erdal, U. of Tulsa, Tulsa, Oklahoma (1998). JULY 199863APPLICATIONSA variety of GLCC applications have requirements that may varyfrom partial to complete gas/liquid separation. Recent technologi-cal development has helped increase deployment of GLCC separa-tor systems in the industry. Successful Applications. The GLCC modeling effort to date hasresulted in successful deployment of the GLCC in a variety ofselected applications, as discussed next.Multiphase Measurement Loop. Most of GLCCs deployed todate (approaching 100) have been configured in a multiphasemetering loop. Fig. 9 is a schematic of the GLCC in a multiphasemetering loop, first introduced by Liu and Kouba,18and Fig. 10shows a GLCC field prototype operated by Chevron in Oklahoma.This type of measurement-loop configuration affords severaladvantages over either conventional separation with single-phasemeasurement or nonseparating multiphase meters. The loop con-figuration is somewhat self-regulating, which can reduce or eveneliminate the need for active level control. The compactness of theGLCC allows the measurement loop to weigh less, occupy lessspace, and maintain less hydrocarbon inventory than a conven-tional test separator. The advantages of a GLCC metering loop overa nonseparating three-phase meter include much improved meter-ing accuracy of individual phases over a wider range of flow ratesand significantly lower cost.For flow conditions where gas carry-under cannot be prevented,a three-phase metering system is required on the liquid leg. In gen-eral, the accuracy of a multiphase meter on the liquid leg benefitssignificantly from removal of some of the gas. Most multiphasemeters have an upper limit on the gas volume fraction allowedthrough the meter to maintain their accuracy specifications. Apartfrom improved accuracy, partial gas separation provides the addi-tional benefit of a smaller, less expensive multiphase meter. Formultiphase meters (whose price scales directly with size), the costsavings of using a smaller meter in conjunction with a GLCC canbe four times the cost of the GLCC.Partial Processing (Separation). A compact GLCC is often veryappropriate for applications where only partial separation of gasfrom liquid is required. One such application is the partial separa-tion of raw gas from high-pressure wells to use for gas lift of low-pressure wells. The GLCC was a central feature in an offshore raw-gas-lift system designed by Chevron that allowed elimination of gascompressor and lift-gas pipelines.19Compact Separation Systems. Compact separation systems are akey element in reducing cost of production operations throughreduction of size and weight. Furthermore, separating a significantFig. 10Chevron-operated GLCC field prototype.Fig. 9GLCC in a multiphase metering loop configuration.64JULY 1998 portion of the gas reduces fluctuations in the liquid flow and mayresult in improved performance of other downstream separationdevices, such as a wellhead desanding hydrocyclone. Chevron isinvestigating the series combination of a GLCC with a free-water-knockout hydrocyclone and a deoiling hydrocyclone in an effort toimprove discharge-water quality. The GLCC was used to control gas/liquid ratio of a two-phase-flow mixture entering a multiphase pump to improve pumping effi-ciency.20Another study showed several combinations of GLCC andjet pumps that could be used to extract energy from high-pressuremultiphase wells to enhance production from low-pressure wells.21Enhancement of Existing Separators. Cyclone separationalready has proved useful in internal separation devices for largehorizontal separators. The GLCC may also function as a usefulexternal preseparation device to enhance performance of existinghorizontal separators (Fig. 11). By separating part of the gas, theseparator level might be raised to increase residence time withoutencountering the mist-flow regime in the vessel. Petrobrs Brazilhas retrofitted an existing separator in one of its fields with a GLCCpreseparator.1Another company is evaluating enhancement oftheir existing test separators with GLCC preseparation.Commercial GLCC Products.Most GLCCs to date have been fieldfabricated for relatively straightforward applications. Applications ofand demand for GLCCs are growing rapidly. Several vendor compa-nies are in the process of incorporating the GLCC into their com-pact-separator product line. Also, as mentioned before, a commercialmultiphase metering system that uses a GLCC and a second-stagehorizontal separator is now available. Greater commercialization willbe needed to meet the growing industry demand.Future Applications. Current successful GLCC applications lendconfidence to future potential GLCC configurations. This requiresenhancement of the existing models and is currently under way.The following are two of the most compelling applications.Subsea Production. The biggest impact to the petroleum industryfrom GLCC technology may be in subsea separation applications.Conclusions in Ref. 22 state that “wellhead separation and pumping isthe most thermodynamically efficient method for wellstream transferover long distances, particularly from deep water.” In a recent study,Prado et al.23argued that this is applicable to shallow and moderatelydeep waters. Undoubtedly, development of marginal offshore fields willdepend on development of efficient and economical technologies.Subsea applications require a high degree of confidence in separatordesign and performance while demanding that the equipment be sim-ple, compact, robust, and economical. Here again, the virtues of theGLCC should place it in good standing among competing technologies.Production Separation. Vertical separators with tangential inletsare fairly common in the oil field. These predecessors of the GLCCare often big and bulky, with perpendicular low-velocity tangentialpipe inlets. The tangential velocities are usually so low that gravi-tational, centrifugal, and buoyancy forces contribute approximate-ly equally to separation. Technological developments in bothGLCC hardware and software should reduce the size and improvethe performance of vertical separators. One challenge in optimizingthe size of a GLCC for production separation is designing a systemthat can respond quickly to surges without serious upsets.CONCLUSIONS The GLCC is a compact, low-cost separator suitable for a wide rangeof applications. The single biggest impediment to widespread imple-mentation of the GLCC is the lack of proven performance-predictiontools that are valid over a wide range of operating conditions. Thesetools are essential to reliable deployment of GLCC technology.Performance-prediction tools based on empirical formulations arelimited in their ability to interpolate or extrapolate to new conditions.CFD simulations can capture much detail of local hydrodynamics butare too computationally intensive, time-consuming, and complicatedto apply to large systems. While CFD modeling is essential to improv-ing our understanding of the flow hydrodynamics in a GLCC, it isimpractical and therefore insufficient as a general design tool.Mechanistic modeling is a reasonable compromise between thesimplicity of empirical formulations and the complexity of CFD.Mechanistic modeling can be validated with CFD simulations tocapture the fundamental physics of the flow without excessivedetail. The combination of CFD and mechanistic modeling pro-vides a realistic approach to obtaining useful tools for design of andperformance predictions for the GLCC. New applications and improved designs are rapidly beingexplored and developed. Several companies are already using theGLCC for some applications (e.g., the multiphase metering loop)and exploring new applications. The GLCC is now commerciallyavailable through some vendors and is being evaluated by othercompanies. Deployment of GLCCs in new and existing applica-tions will flourish as understanding of and confidence in predict-ing flow behavior and performance of the GLCC matures.NOMENCLATUREd=GLCC diameter, L, in.db=bubble diameter, L, md100=minimum bubble diameter that always migrates from GLCC wall to gas core, L, mL=length, L, ftp=pressure, m/Lt2, psigr=radial coordinate, L, ftR=GLCC radius, L, in.Rcap=bubble-capture radius, L, in.vgs=superficial gas velocity, L/t, ft/secvLs=superficial liquid velocity, L/t, ft/secvt=tangential velocity, L/t, ft/secvtis=tangential velocity at inlet slot, L/t, ft/secvz=axial velocity, L/t, ft/secyL0=zero-net-liquid-flow holdup, fractionx=axial coordinate, L, ft=void fractionACKNOWLEDGMENTSWe thank Chevron Petroleum Technology Co. and the other mem-bers of the Tulsa U. Separation Technology Projects (TUSTP) forsupporting this work.REFERENCES1.Gomez, L.E.: “A state-of-the-art Simulator and Field ApplicationDesign of Gas-Liquid Cylindrical Cyclone Separators,” MS thesis, U.of Tulsa, Tulsa, Oklahoma (1998).2.Arpandi, I. et al.: “Hydrodynamics of Two-Phase Flow in Gas/LiquidCylindrical-Cyclone Separators,” SPE Journal (December 1996) 427.Fig. 11Enhancement of existing conventional separator with aGLCC.1 JULY 1998653.Kouba, G.E. and Shoham, O.: “A Review of Gas-Liquid CylindricalCyclone (GLCC) Technology,” paper presented at the 1996 Intl. IBCConference on Production Separation Systems, Aberdeen, 2324 April.4.Kouba, G.E., Shoham, O., and Shirazi, S.: “Design and Performance ofGas-Liquid Cylindrical Cyclone Separators,” Proc., BHR GroupSeventh Intl. Conference on Multiphase Flow, Cannes, France(1995) 307.5.Wang S.: “Control Strategies for Gas-Liquid Cylindrical CycloneSeparators,” MS thesis, U. of Tulsa, Tulsa, Oklahoma (1997).6.Movafaghian, S.: “The Effects of Geometry Fluid Properties andPressure on the Flow Hydrodynamics in Gas-Liquid CylindricalCyclone Separators,” MS thesis, U. of Tulsa, Tulsa, Oklahoma (1997).7.Millington, B.C. and Thew, M.T.: “LDA Study of ComponentVelocities in Air-Water Models of Steam-Water Cyclone Separators,”Proc., Third BHRA Intl. Conference on Multiphase Flow, The Hague,The Netherlands (1987) 115.8.Kolpak, M.: “GLCC Level-Pressure Sensitivity, Level Control andTurbulent Diffusion” internal report, Arco Oil and Gas Co., Plano,Texas (1994