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Title: Utility seeks to integrate heat recovery, flue-gas treatment

Journal Article · · Power; (United States)
OSTI ID:6358686

To avoid corrosion damage that can occur when water and acids condense in flue-gas systems, utility powerplants typically maintain flue-gas-outlet temperatures above 300 F, with 250 F as the minimum acceptable. Consolidated Edison Co. of New York Inc. is defying this standard practice by extracting additional useful heat from the flue-gas streams of three 600,000-lb/hr, oil-fired boilers. The utility installed a condensing heat exchanger (CHE) at its 74th St station in February 1992 as the first phase of an R and D project designed to quantify the many benefits of this technology. Recall that stack exhaust heat is the second largest thermodynamic loss for a powerplant. Corrosion- and chemical-resistant CHEs have been widely used by non-utility industrial plants to improve efficiency by recovering additional sensible heat from the flue gas - plus the latent heat released when moisture condenses. The recovered energy is typically used to heat feedwater or condensate before the first-stage heater. Result: cycle efficiency is greatly improved, reducing fuel consumption and/or increasing the total steam available for power generation or district heating/cooling. Con Edison is taking the technology beyond heat recovery. The second phase of ConEd's research, now under way at the utility's oil-fired Ravenswood station, entails demonstrating CHEs as a new type of wet scrubber for efficient removal of volatile and semi-volatile trace elements, sub-micron-size particulate matter, SO[sub 2], SO[sub 3] and hydrogen chloride (HCl). If successful, this could be the first stand-alone system capable of simultaneously reducing heat rate and accomplishing flue-gas cleanup goals.

OSTI ID:
6358686
Journal Information:
Power; (United States), Vol. 137:5; ISSN 0032-5929
Country of Publication:
United States
Language:
English