Air Preheater Retrofit and Enhancement0 pages

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RETROFITS AND ENHANCEMENTS

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ARE COST EFFECTIVE WAYS OF

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IMPROVING BOILER PERFORMANCE

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Howden

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PREHEATER RETROFIT AND ENHANCEMENT

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AIR PREHEATERS PLAY AN INTEGRAL

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PART IN THE EFFICIENT OPERATION OF

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POWER PLANTS. AS THE CONDITIONS

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IN THE PLANT CHANGE, FOR EXAMPLE

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BY CHANGES IN FUELS OR OPERATING

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CYCLES, DEMANDS ON THE AIR

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PREHEATERS ALSO CHANGE.

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WHEN THIS HAPPENS, HOWDEN'S

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EXPERIENCED ENGINEERS AND

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SITE SPECIALISTS CAN PROVIDE

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A COMPLETE ADVISORY SERVICE.

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HOWDEN KNOW-HOW

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UPGRADING AIR PREHEATERS TO THE

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LATEST TECHNOLOGY STANDARDS

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BRINGS A WIDE RANGE OF BENEFITS.

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• It reduces the power demands of the

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draught fan, and thus raises the saleable

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power output.

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• If the operating conditions have changed,

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replacement elements can improve

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overall performance significantly.

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• It helps to eliminate the temperature dilution

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effect of air leakage, and so helps reduce

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corrosion downstream of the air preheater.

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• By reducing leakage it makes more air

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available at the coal mills, ensuring an

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adequate supply of pulverised fuel to the

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burners - especially when the coal is wet -

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and compensating for shortfalls in output.

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Reduced leakage also lessens the flow

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through the forced draught and induced

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draught fans, and thus eliminates the

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output shortfall that would be caused

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by overloading the fans.

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A routine cleaning of the elements with

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highly efficient sootblowers will ensure

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a steady heat transfer and minimise

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pressure drop in the plant system.

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If operating condition has changed then

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replacement elements can improve

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overall performance significantly.

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Upgrading or enhancing an air preheater is

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usually one of the most cost-effective ways of

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Improving boiler performance. Dramatic results

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can be achieved by either increasing thermal

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performance or reducing leakage. Before

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retrofitting FGD plant downstream of the boiler,

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It is always worth investigating air preheater

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leakage, which can create unnecessary

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demands elsewhere in the system. Improving

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the air preheater sealing system can actually

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reduce the size of the FGD plant, with obvious

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cost savings.

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In many cases, heat recovery can be increased

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by installing higher performance elements,

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or increasing their overall depth, or both.

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