Cilj je ovoga rada ukratko predstaviti poboljšanja i optimizaciju plinske turbine AE64.3A u projektnoj fazi i također rezultate dobivene ispitivanjem tijekom puštanja u pogon u termoelektrani Vlore. Cijelo je vrijeme ova plinska turbina radila na destilatu goriva i tako postala prototip, a njeno radno iskustvo jedinstveno. Gorionik AE64.3A+ zasniva se na hibridnom (difuzija/gotova smjesa) principu projektiranja koji mu omogućuje nisku emisiju NOx i CO te stabilno i pouzdano izgaranje i pogonskog plina i goriva. Plinska turbina AE64.3A+ instalirana je u termoelektrani Vlore i nakon ispitivanja tijekom probnog rada u lipnju 2010 nastavila je raditi s velikom učinkovitošću zahvaljujući optimizaciji u fazi projektiranja.The aim of this paper is to make a short presentation of the improvement and optimization of the Gas Turbine in the design phase and also show the results achieved during the commissioning and the performance test in the Vlore PP. All the time this gas turbine operated on distillate fuel oil and this made it a prototype and its operating experience unique. The AE64.3A+ burner is based on the hybrid (diffusion/premix) burner design principle that enables it to perform low NOx and CO emission and stable and reliable combustion of fuel gas and fuel oil. The AE64.3A+ gas turbine is installed in the CCPP of Vlore and after the commissioning tests, carried out in the June 2010, continued to operate with a high performance due to the optimization made during the design phase

Klodian Gumeni

Gumeni, Klodian

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1Introduction2AE64.3A+ gas turbine2.1General design features ofAE64.3A+Machine body(F )The growth of power markets stresses the importanceof optimizing power plant performance and creates the needto improve and upgrade the existing power generationplants. Thus a gas turbine with medium power output isregarded as a strategic asset in gaining competitiveness inenergy business.In such a challenging scenario, a new state-of-the artAE64.3A (hereinafter defined as AE64.3A+) ig. 1 gasturbine has been developed by Ansaldo Energia, enhancingperformance, operational and dynamic features.The AE64.3A+ gas turbine is a single shaft, cold enddrive, annular combustor, heavy-duty gas turbine designedfor 50 Hz operations. The gas turbine is suited to run in baseload operation and can be used both in open cycle and incombined cycle operations.The AE64.3+ gas turbine is based on a mono shaftdesign: it includes fifteen (15) stages axial compressor and afour (4) stage axial turbine having a common rotor. Therotor (Fig. 2) consists of a front shaft section, fifteen (15)compressor blade disks, a central hollow shaft section, four(4) turbine blade disks and a rear shaft section, all heldtogether by a single central tie bolt with a clamping nut at theturbine end. Each disk of the rotor has radial Hirth teeth onboth sides; the Hirth serrations provide radial alignmentbetween the rotor sections, ensuring torque transmission663K  Gumeni.ISSN 1330-3651UDC/UDK 621.438.081:658.512.2IMPROVEMENT AND OPERATING EXPERIENCE OF THE AE64.3A GAS TURBINEINSTALLED IN CCPP OF VLOREKlodian GumeniThe aim of this paper is to make a short presentation of the improvement and optimization of the Gas Turbine in the design phase and also show the resultsachieved during the commissioning and the performance test in the Vlore PP. All the time this gas turbine operated on distillate fuel oil and this made it aprototype and its operating experience unique. The AE64.3A+ burner is based on the hybrid (diffusion/premix) burner design principle that enables it toperform low NOx and CO emission and stable and reliable combustion of fuel gas and fuel oil. TheAE64.3A+ gas turbine is installed in the CCPP of Vlore andafter the commissioning tests, carried out in the June 2010, continued to operate with a high performance due to the optimization made during the design phase.Keywords: gas turbine, hybrid burner, combustion chamber, loads rejectionProfessional paperCilj je ovoga rada ukratko predstaviti poboljšanja i optimizaciju plinske turbine AE64.3A u projektnoj fazi i također rezultate dobiveneakoji mu omogućuje nisku emisijunastavila je raditi s velikom učinkovitošću zahvaljujući optimizaciji u fazi projektiraispitivanjem tijekompuštanja u pogon u termoelektrani Vlore. Cijelo je vrijeme ova plinska turbin radila na destilatu goriva i tako postala prototip, a njeno radno iskustvojedinstveno. Gorionik AE64.3A+ zasniva na hibridnom (difuzija/gotova smjesa) principu projektiranja NOx i CO testabilno i pouzdano izgaranje i pogonskog plina i goriva. Plinska turbina AE64.3A+ instalirana u termoelektrani Vlore i nakon ispitivanja tijekom probnograda u lipnju 2010 nja.sejeKljučne riječi: plinska turbina, hibridni gorionik, komora izgaranja, odbacivanje opterećenjaStručni članakPlinska turbina AE64.3A instalirana u termoelektrani Vlore - poboljšanje i radno iskustvoTehni ki vjesnikč 18, 4(2011)  663-667,Plinska turbina AE64.3A instalirana u termoelektrani Vlore - poboljšanje i radno iskustvoand allowing free relative radial expansion and contraction.Such a construction is of particular significance for the lifeof the rotor parts in response to changes in the operatingconditions and in the temperature distribution in the rotor; itis the reason for the short start-up and loading/unloadingtimes of the AE64.3A+ gas turbine and for their problem-free operation under all steady-state and non-steady-staterotor temperature conditions.The rotor resulting from such a construction is a self-supporting drum with low weight and high stiffness;therefore it can be supported by only two bearings, one atthe front shaft section and one at the rear shaft section. Thiseliminates the need for an additional bearing between thecompressor and the turbine. The bearing at the compressorend is a combined journal and thrust bearing designed toaccommodate the axial thrust of the rotor.The two bearings are located outside the pressurizedregion of the gas turbine, providing the basis for constantgood alignment and excellent running qualities.All the turbine stator vanes and rotor blades are air-cooled, with the exception of the last stage ones. Cooling airis provided at different pressure and temperature levels bycompressor extraction, in order to provide the best possiblecooling effect and, at the same time, to provide optimal unitthermal performance.The cooling air, after flowing through blades and vanes,discharges into the hot gas stream.The AE64.3A+ gas turbine design is based on the two-shell design principle from the section of the compressorstage 10 to the turbine outlet, together with the combustionchamber. On the contrary, the casing from the compressorinlet to the section of the compressor stage 9 is featured bythe single-shell design principle.The major advantage of the two-shell design principleis that the mechanical and thermal loads on the casings areclearly separated; all mechanical loads due to internalpressure are taken by the outer casing on which the thermalloads are low, while all thermal loads are taken by the inner664 Technical Gazette 18, 4(2011)  663-667,K  Gumeni.combustion with fuel gas and fuel oil.The burner aerodynamics is given by 2 concentric, co-rotating swirlers (axial and diagonal) and the burnerconsists of an unchanged central diffusion burner suitablefor operation with fuel oil and gas. This diffusion burneralso contains the pilot burner for premix gas operation.The premix gas distributing pipes are integrated into theswirl generating blades. This minimizes the danger of localauto-ignition and improves the mixing with the airincoming to the diagonal swirler.Improvement and operating experience of the AE64.3A gas turbine installed in CCPP of Vlorecasing on which the mechanical loads are low.The generator is driven from the compressor (cold) endand it is coupled via a gear box to the gas turbine shaft. Thisfacilitates the connection of an optimum-geometry exhaustgas diffuser and a low-loss exhaust gas train to a heatrecovery boiler without significant changes in direction.The AE64.3A+ gas turbine is equipped with an annularcombustion chamber and 24 dry low NO burners for bothfuel gas and fuel oil.The combustion zone ig. 3 is wrapped around the gasturbine first stage inlet section.The combustion chamber is mounted inside the centresection of the outer casing.The combustion chamber casing is formed by low alloysteel cast shells, which are completely enveloped by thecompressor discharge air. They are thus not exposed to thelocal variations in temperature of the surface in contact withthe hot gas. The surface exposed to the hot gas is formed byheat shields made of metal tiles with a ceramic oxide layeron their surface.(F )Combustion chamberxFigure 1 3D Model of a V64.3A+ Gas TurbineFigure 2 Rotor view from compressorBurnersThe AE64.3A+ burner is based on the hybrid(diffusion/premix) burner design principle, that is able toperform low NO and CO emissions and stable and reliablexFigure 3 Rotor view with annular combustion chamberThe premix oil operation mode is achieved by means ofsuitable oil nozzles downstream the diagonal swirler blades:the oil jet is atomized by the incoming air and the dropletsvaporize and mix with air before the outlet.The hybrid burner combustor combines all theadvantages of optimal combustion, including:- low NO and CO emissions- low pressure loss- high operating flexibilityfully symmetrical designoptimal size and number of burnerscompact design with good accessibility.Significant improvement margins do exist to allow theperformance increase of gas turbineAE64.3A, so to achievewhat will be hereinafter defined asAE64.3A+.Such performance increase is operatively feasible byintroducing on the previous model AE64.3A, in a more orless extended way, some of the features of the higher ratedAE94.3A(4) gas turbine.The modifications made in changing AE64.3A toAE64.3A+ chiefly consist of:Compressor redesigned to allow, with an (almost) equalinlet and outlet cross section, to have a definitely higherair flow rate and a surge margin as much improved.Casing and compressor bearing redesigned for bothmechanical and fluid-dynamic reasons.Turbine modified mainly as concerns the last stage, toincrease the efficiency of flow rate.Casing and arms supporting the turbine bearingredesigned, with arms having airfoil profile instead ofstraight profile.x---3Design evolution of AE64.3A+ gas turbine665Tehni ki vjesnikč 18, 4(2011)  663-667,K  Gumeni.Combustion chamber modified as concerns both thegeometry (turbine interface).Unchanged burners, taking into account the latestevolutions of the HR3 burners.Cooling air system of the turbine modified both for thepresence of a redesigned compressor and also for anadditional air bleed inside the rotor.Other components modified due to what is describedabove (e.g. the rotor, but also the outer casings,supports, etc.)Fig. 4 resumes the main improvements on AE64.3A+Gas Turbine:a) Increase of compressor mass flowb) Optimization of last turbine stagec) Optimization of turbine cold-endd) Burner improvemente) TBC (Thermal Barrier Coatings) on turbine stages.4Performance of a AE64.3A+ gas turbineT.In Tabs. 1 and 2 performances of a AE64.3A+ gasturbine  are  listed  both  in  COBRA (Combined  BraytonRankine) cycle arrangement ( ab. 1) and in ISO condition(Tab. 2).(F )(F )ISO condition with:- Condenser vacuum = 0,035 bar- GT inlet pressure loss = 10 mbar ISO- GT exhaust pressure loss = 30 mbar ISOThe Power Plant of Vlore (Albania) is a CombinedCycle based on one dual fuel gas turbine model AnsaldoAE64.3A+, one horizontal fired HRSG, triple pressuresections without reheater, one Ansaldo Energia steamturbine rating approx 30 MWe with water cooled condenser.The plant site is located on a six hectare green field siteadjacent to the offshore oil tanker terminal located on theAdriatic coast north of the Port of Vlore approximately sixkm from the Port of Vlore ig. 6 .The AE64.3A+ gas turbine for Vlore Project ig. 7was delivered during July 2008 and started its operation inthe beginning of 2010.5Vlore CCPP (Combined Cycle Power Plant) rojectPPlinska turbina AE64.3A instalirana u termoelektrani Vlore - poboljšanje i radno iskustvoFigure 4 Main areas of improvements on a AE64.3A+ gas turbineFigure 5 3-D meshed model of a AE64.3A+ gas turbineTable 1 Performances of AE64.3A+ Gas Turbine in different cyclearrangementModel ofgas turbineFrequencyHzContinuousoutputMWHeatratekJ/kWhEfficiency%1xV64.3A 50/60 112 6698 53,752xV64.3A 50/60 224 6689 53,82Table 2 Performances of AE64.3A+ gas turbine, ISO conditionThermodynamic Data Iso Base Load V64.3ATurbine Inlet Temp. acc. to ISO2314 , °C 1190Pressure Ratio 16,7Power Output at generator terminal, MW 75Efficiency at generator terminal 35,9Exhaust Gas Mass Flow, kg/s 213Exhaust Gas Temperature , °C 574Figure 6 Aerial view of the bay of Vlore (Albania)Figure 7 AE64.3A+ gas turbine installed in the Vlore site666 Technical Gazette 18, 663-667(F Fig.)The gas turbine was supplied in accordance to thestandard and proven design of the manufacturer, optimizingthe need for burning fuel oil in continuous operation.As a fact, one of the main operational features of theAE64.3A+ installed in Vlore will be the continuousoperation on Fuel Oil.Aiming to enhance its own field experience, GasTurbine Engineering Department of Ansaldo Energiadecided to install additional instrumentation ig. 8 and9 for monitoring of the state of the art AE64.3A+ gasturbine installed in Vlore.The on-line monitoring system will be used to deeperinvestigate the GT operation on fuel oil duringcommissioning phase.In particular, AE64.3A's body was equipped withseveral measuring points: different stages of compressor,blow-off lines, combustion chamber, cooling lines, shaftand bearings.As a final result, all the measuring points resulted in alarge set of temperature, pressure, vibration and positioningdata.The whole system is made up of the followingpackages: sensing, data acquisition, characterization,condition monitoring and feature extraction packages.6High-technology additional instrumentation for the VloreProjectF 1Several signal processing methods, namely, cross-correlation, resample, short-time Fourier transform andstatistical process control, are developed to extract severalvalues considered highly representative of GT operation.The AE64.3A+ installed in Vlore started itscommissioning at the beginning of 2010.In the following, the main important operatingconditions tested in Vlore during commissioning aredescribed in detail.All pictures from 10 to 12 are directly taken asscreenshots from GT control system during relevant testsperformed on site. Standard KKS (identification system forpower station) tag for key features is in evidence.In ig. 0 a start-up and synchronization is represented.In the start-up process, the fuel oil flame is ignited by anignition flame produced by propane gas coming from theignition gas system. The Start-Up is performed in Diffusionmode and once the GT has been started, it is ready to besynchronized. The load jump for synchronization is approx5 MW.7Operating experienceImprovement and operating experience of the AE64.3A gas turbine installed in CCPP of Vlore K  Gumeni.Figure 8 Instrument racks in Vlore for additional instrumentationFigure 9 Pressure measurements on AE64.3A+ installed in VloreFigure 10 Start-up and synchronizationFIn ig. 11 a change over from diffusion to premix flameis shown.Among other permissive criteria, the change over fromdiffusion operation to premix operation can only beperformed in a certain range defined by the values of theturbine exhaust temperature and IGV (inlet guide van)position.The load set point is frozen during complete changeover. In case of fuel oil diffusion operation with waterinjection, before proceeding the water injection systemmust be switched off during the change over. To prevent fueloil cracking, a water emulsion system, together with a lowerpressure purging system provides flushing water insufficient capacity and at a sufficient pressure to premixnozzles.Finally, in Fig. 12 the load rejection performed frombase load is included.In general, starting from any condition, in case of loadrejection the water injection is tripped. The fuel oil premixmode system is even tripped and the GT remains in stablediffusion dry mode.667Tehni ki vjesnikč 18, 4(2011)  663-667,8Conclusions9References,, ,, ,.On the basis of its operating experiences and taking intoaccount specific needs of its customers, Ansaldo Energiahas upgraded its medium-rated-powerAE64.3A gas turbinewith several improvements, enhancing performances andoperational features as follows:The output power from 67 5 to 75 MWEfficiency from 35 1 to 35 9 %Fuel consumption from 4 58 to 4 64 kg/sExhaust gas mass flow from 193 to 213 kg/sAll operating conditions of the GT were successfullytested during commissioning phase in the Vlore PowerPlant.In the light of this scenario, Ansaldo Energia AE64.3Agas turbine can be undoubtedly regarded as an excellentchoice for energy power market according to its engineeringguiding principles and its operational and dynamic features.[1] Kehlhofer RCombined – Cycle Gas & Steam Turbine Power PlantsPennWell Corporation[2] Raja, A. K. Amit Praakash Srivastava, Manish Dwivedi,Power Plant Engineeringhttp://ebooksbyashwingami.blogspot.com/2011/power-plant-engineering-by-akraja-amit.html, .; Hannemann, F.; Stirnimann, F.; Rukes, B., 3rdEdition, , 2009..K  Gumeni. Plinska turbina AE64.3A instalirana u termoelektrani Vlore - poboljšanje i radno iskustvoFigure 11 Change over from diffusion oil to premix oilFigure 12 Load rejection from base loadAuthor's address:Klodian Gumeni, MScKESH Albania Power CorporationAddress: Blloku Vasil Shanto, Tirana, AlbaniaTel/Fax +355 (0) 4 262055Mobile +355 (0) 692096286E-Mail: gumenik@kesh.al

Improvement and operating experience of the AE64.3A gas turbine installed in CCPP of Vlore

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