RETROFITS AND ENHANCEMENTS ARE COST EFFECTIVE WAYS OF IMPROVING BOILER PERFORMANCE AIR PREHEATER RETROFIT AND ENHANCEMENT HOWDEN KNOW-HOW AIR PREHEATERS PLAY AN INTEGRAL PART IN THE EFFICIENT OPERATION OF POWER PLANTS. AS THE CONDITIONS IN THE PLANT CHANGE, FOR EXAMPLE BY CHANGES IN FUELS OR OPERATING CYCLES, DEMANDS ON THE AIR PREHEATERS ALSO CHANGE. WHEN THIS HAPPENS, HOWDEN’S EXPERIENCED ENGINEERS AND SITE SPECIALISTS CAN PROVIDE A COMPLETE ADVISORY SERVICE. UPGRADING AIR PREHEATERS TO THE LATEST TECHNOLOGY STANDARDS BRINGS A WIDE RANGE OF BENEFITS. • It reduces the power demands of the draught fan, and thus raises the saleable power output. • If the operating conditions have changed, replacement elements can improve overall performance significantly. • It helps to eliminate the temperature dilution effect of air leakage, and so helps reduce corrosion downstream of the air preheater. • Reduced leakage also lessens the flow through the forced draught and induced draught fans, and thus eliminates the output shortfall that would be caused by overloading the fans. • A routine cleaning of the elements with highly efficient sootblowers will ensure a steady heat transfer and minimise pressure drop in the plant system. • By reducing leakage it makes more air available at the coal mills, ensuring an adequate supply of pulverised fuel to the burners – especially when the coal is wet – and compensating for shortfalls in output. Upgrading or enhancing an air preheater is usually one of the most cost-effective ways of improving boiler performance. Dramatic results can be achieved by either increasing thermal performance or reducing leakage. Before retrofitting FGD plant downstream of the boiler, it is always worth investigating air preheater leakage, which can create unnecessary demands elsewhere in the system. Improving the air preheater sealing system can actually reduce the size of the FGD plant, with obvious cost savings. In many cases, heat recovery can be increased by installing higher performance elements, or increasing their overall

AIR PREHEATER RETROFIT AND ENHANCEMENT Selecting from our broad range of profiles, we can supply direct replacements for all of the element types commonly used in air preheaters, regardless of make. In many cases alternative profiles or arrangements can improve performance significantly, particularly if the operating conditions have been changed since the original elements were specified. Improving the use of space within the rotor can also make significant contributions to overall boiler efficiency. In several designs of air preheater, leakage can significantly increase over time. Known as ‘leakage...