Plate Heat Exchangers Recycle Heat To District Heating Loop, Helping Increase Thermal Efficiency By 20%
An integrated waste management and energy company in Malmö, Sweden, is using Tranter Plate Heat Exchangers to capture waste heat from boiler flue gas condensate and cool this stream prior to purification and discharge. Gas cleaning from the waste-to-energy boiler takes place in a four-stage scrubber. Heat in the condensate from the top stage of the scrubber is transferred to the district heating loop through a Tranter Model GXD-205 exchanger. During the exchange, the scrubber condensate is cooled to a temperature 1–2 °C (1.8–3.6°F) above the incoming district heating water.
Two other heat exchangers complete the condensate heat recovery and cooling process. A Model GCD-016 uses district heating water as cooling media for the Stage 4 flue gas condensate. A GLD-013 unit uses ground water to further cool the Stage 4 water and also to cool process water from scrubber Stage 3, the sulfur dioxide step.
Plates for all three units were manufactured in 254 SMOTM stainless steel (1.4547) to withstand chlorides and fluorides in the flue gas condensate. The flue gas condensate heat recovery strategy has potential for any boiler flue gas stream 150°C (300°F) or above.
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Tranter GCD-016 and GLD-013 Plate Heat Exchangers recycle heat from upper scrubber stages and cool process water for temperature-controlled outflow.