[in detail energy] twentyfour7. - enventure...

[IN DETAIL ENERGY] Twentyfour7.

Avoiding plant downtimeThe main challenge when performing conversion workis minimizing the impact on normal plant operation.Activities are therefore timed to coincide with regularmaintenance work, i.e. when the engines have beenstopped for their 24,000-hour overhaul.The installation of gas pipelines involves welding

1 New gas feed systems operations and pulling a variety of cables. One of_ ...__ ·__ ._,__ ._._..__ .._L_~~~~'!":'.!Q~.Qf~I?:..!:1FQ.!.~~~I~iQ!1 t~~~~~~ on_I1~~~~_..._th~.~~.~!:l...c:h<lH~~s ..~_<:~.or4~~:l!.!!:l.g..:;.!.t:!:_~ti.Y-i~ies,

i gas involves replacing some engine components, with balancing plant operation requirements against the! the number of components being changed dependent demands of the conversion work so that both runi on the equipment's age. The main change involves the smoothly.i addition of a new gas-feed system together with changes To keep plant downtime to a minimum, engines will! to the engine's control and monitoring systems. The be converted one at a time. The gas systems will be

plant conversion process consists of modifications to assembled while the engines are running on HFO andgas handling systems and control systems. then swapped over as gas becomes available. AccordingWartsiIa offers three types of gas conversion to the IPP's power purchase agreements, each of the

technology: gas diesel (GD); low-pressure natural gas three plants is contracted to deliver 60-65 MW This(SG) and dual-fuel (DF). All three Manaus plants will means that only four out of the five engines at eachundergo GD conversions. Gas diesel technology is plant are in continuous operation, with the fifth enginebased on the injection of natural gas at high pressure on standby. Conversion work can therefore be carriedas part of the diesel cycle, which means that engine out on the standby engine.modifications are limited to the injection equipmentand associated control systems.The resulting GD engine is a dual-fuel device designed

to operate in two fuel modes. In the liquid-fuel mode,LFO, HFO or crude oil is used as the main fuel andthe engine operates on the ordinary diesel cycle. In gas-fuel mode, natural gas is the main fuel and ignition isperformed using a small quantity of liquid fuel.

ALL THREEMANAUS

PLANTS WILLUNDERGO GDCONVERSIONS.

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by three Brazilian IPPs - Geradora de Energia doAmazonas SIA, Companhia Energetica Manauara, andRio Amazonas Energia SA (part of Multiner SIA) - toconvert their generating stations. All three companieshave power plants located in the City of Manaus andindicated their desire to be able to use every possiblefuel alternative in the future.While the reasons behind this move include

environmental considerations, the need for redundantgenerating capacity and the ability to take advantageof the lowest-cost fuel options, the key driver has beenthe expectation that natural gas will be available in theregion in 2010. The gas conversion projects will becarried out at all three power plants concurrently.Each of the three 85 MW power plants has five

Wartsila 18V46 engines. When they were deliveredin 2006, gas was not available. The plants were,however, pre-designed to facilitate the conversion workwhich allows them to be switched from their currentbaseload operation using HFO to operating on gas.Wartsila is currently operating and maintaining allthree plants under contract, and will therefore ensurethat they continue delivering optimum performanceand levels of reliability after the conversion work hasbeen completed.

Extra compression requiredPrior to conversion, WartsiIa 18V 46 engines have asingle fuel-feed system located at the top of the enginecylinders. This handles the liquid fuels (HFO or LFO).

As the engines will continue to need pilot fuel in smallquantities, the conversion process involves adding a gasfeed consisting of two injectors. Having two separatefuel-feed systems means that the engines can be runon either gas or liquid fuel, with the choice dependingon how much gas is available.One consequence of selecting the GD option is that

high-pressure gas at around 350 bar will be requiredso an additional compressor is needed to boost thefuel pressure from its normal 20-40 bar. Althoughthis gas compressor section is a relatively expensivecomponent, its cost is offset by the flexibility of beingable to switch fuels.The gas fuel system supplies GD engines with clean

gas at constant pressure and temperature. The maincomponents of the system are a gas compressor skida buffer tank, a valve station, interconnecting pipesand double-wall ventilation system.

Largest project to dateWith a combined value of more than EUR 48 million,these three plant conversions represent the biggestproject of its kind ever undertaken by Wartsila Services.Its size and scope, together with the fact that the workis to be carried out at three separate sites, make it aninteresting challenge.Gas pipelines are now under construction and gas is

expected to be available in 200912010. This will allowpre-commissioning of the first units to begin during thesecond quarter of201O.The three plants are scheduledto be fully operational in October 2010 .•