Vertical Tube, Variable Pressure Furnace for Supercritical Steam Boilers

摘要

The U. S. Department of Energy (DOE) is developing highlyefficient, low-emission, and low-cost power generation technologywith industry participation for future power plants. As partof the DOE advanced combustion program, The Babcock &Wilcox Company/McDermott Technology Inc. (B&W/MTI) willbe testing a system that emulates a vertical tube, variable pressurefurnace designed for supercritical boilers. Two types ofsupercritical boiler furnace designs are in use today, both requiringhigh mass flow per tube for cooling. One operates at a constantfluid pressure in the furnace and utilizes vertical tubes, andthe other allows the fluid pressure to vary with changing loadsand utilizes a spiral furnace design. The constant pressure furnacedesign has been used primarily in the U.S. while the variablepressure design has been dominant in Europe.B&W/MTI has completed the design of a system to test thelow mass flow, vertical tube, variable pressure furnace design atAllegheny Energy Supply Company's Hatfield's Ferry Unit #3, a575 MWe B&W supercritical boiler. Test panels, approximately100 feet long, will be installed on the front and sidewalls of theboiler that provide differing heat flux patterns. The testing willdemonstrate the flow characteristics and dynamic stability of theoptimized multi-lead ribbed tube that is key to this furnace design,and validate the models for theoretical analysis and design.The low mass flow vertical tube furnace design will allow variablepressure operation, on/off cycling, and rapid load changing,that are the same operating advantages seen in a spiral design.This vertical tube design, however, will have additional benefitsover the spiral design that include lower fabrication cost, lower construction cost, 45% lower furnace pressure drop (i.e., lessfeed pump power needed), increased operating margin againsttube overheating, and less maintenance cost. Startup and testingis planned for the spring-summer of 2002.In this paper, design features of the optimized multi-lead ribbedtube and the test plan will be presented.