Air Preheater Retrofit and Enhancement0 pages
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nnnnRETROFITS AND ENHANCEMENTS
nnnnARE COST EFFECTIVE WAYS OF
nnnnIMPROVING BOILER PERFORMANCE
nnnnHowden
nnnnPREHEATER RETROFIT AND ENHANCEMENT
nnnnAIR PREHEATERS PLAY AN INTEGRAL
nnnnPART IN THE EFFICIENT OPERATION OF
nnnnPOWER PLANTS. AS THE CONDITIONS
nnnnIN THE PLANT CHANGE, FOR EXAMPLE
nnnnBY CHANGES IN FUELS OR OPERATING
nnnnCYCLES, DEMANDS ON THE AIR
nnnnPREHEATERS ALSO CHANGE.
nnnnWHEN THIS HAPPENS, HOWDEN'S
nnnnEXPERIENCED ENGINEERS AND
nnnnSITE SPECIALISTS CAN PROVIDE
nnnnA COMPLETE ADVISORY SERVICE.
nnnnHOWDEN KNOW-HOW
nnnnUPGRADING AIR PREHEATERS TO THE
nnnnLATEST TECHNOLOGY STANDARDS
nnnnBRINGS A WIDE RANGE OF BENEFITS.
nnnn• It reduces the power demands of the
nnnndraught fan, and thus raises the saleable
nnnnpower output.
nnnn• If the operating conditions have changed,
nnnnreplacement elements can improve
nnnnoverall performance significantly.
nnnn• It helps to eliminate the temperature dilution
nnnneffect of air leakage, and so helps reduce
nnnncorrosion downstream of the air preheater.
nnnn• By reducing leakage it makes more air
nnnnavailable at the coal mills, ensuring an
nnnnadequate supply of pulverised fuel to the
nnnnburners - especially when the coal is wet -
nnnnand compensating for shortfalls in output.
nnnnReduced leakage also lessens the flow
nnnnthrough the forced draught and induced
nnnndraught fans, and thus eliminates the
nnnnoutput shortfall that would be caused
nnnnby overloading the fans.
nnnnA routine cleaning of the elements with
nnnnhighly efficient sootblowers will ensure
nnnna steady heat transfer and minimise
nnnnpressure drop in the plant system.
nnnnIf operating condition has changed then
nnnnreplacement elements can improve
nnnnoverall performance significantly.
nnnnUpgrading or enhancing an air preheater is
nnnnusually one of the most cost-effective ways of
nnnnImproving boiler performance. Dramatic results
nnnncan be achieved by either increasing thermal
nnnnperformance or reducing leakage. Before
nnnnretrofitting FGD plant downstream of the boiler,
nnnnIt is always worth investigating air preheater
nnnnleakage, which can create unnecessary
nnnndemands elsewhere in the system. Improving
nnnnthe air preheater sealing system can actually
nnnnreduce the size of the FGD plant, with obvious
nnnncost savings.
nnnnIn many cases, heat recovery can be increased
nnnnby installing higher performance elements,
nnnnor increasing their overall depth, or both.
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