The Roadmap for Process Heating Technology (March 16, 2001), identified the following priority R&D needs: “Improved performance of high temperature materials; improved methods for stabilizing low emission flames; heating technologies that simultaneously reduce emissions, increase efficiency, and increase heat transfer”. Radiant tubes are used in almost every industry of the future. Examples include Aluminum re-heat furnaces; Steel strip annealing furnaces, Petroleum cracking/ refining furnaces, Metal Casting/Heat Treating in atmosphere and fluidized bed furnaces, Glass lair annealing furnaces, Forest Products infrared paper driers, Chemical heat exchangers and immersion heaters, and the indirect grain driers in the Agriculture Industry. Several common needs among the industries are evident: (1) Energy Reductions, (2) Productivity Improvements, (3) Zero Emissions, and (4) Increased Component Life. The Category I award entitled “Proof of Concept of an Advanced Process Heater (APH) for Steel, Aluminum, and Petroleum Industries of the Future” met the technical feasibility goals of: (1) doubling the heat transfer rates (2) improving thermal efficiencies by 20%, (3) improving temperature uniformity by 100oF (38 oC) and (4) simultaneously reducing NOx and CO2 emissions. The APH addresses EERE’s primary mission of increasing efficiency/reducing fuel usage in energy intensive industries. The primary goal of this project was to design, manufacture and test a commercial APH prototype by integrating three components: (1) Helical Heat Exchanger, (2) Shared Wall Radiant U-tube, and (3) Helical Flame Stabilization Element. To accomplish the above, a near net shape powder ceramic Si-SiC low-cost forming process was used to manufacture the components. The project defined the methods for making an Advanced Process Heater that produced an efficiency between 70% to 80% with temperature uniformities of less than 5oF/ft (9oC/m). Three spin-off products resulted from this project: (1) a low-cost, high-temperature heat exchanger, (2) a new radiant heat transfer system, and (3) a hybrid or integral advanced process heater that incorporates a high surface area ceramic heat exchanger and burner combined with either a metallic or ceramic radiant tube and heat transfer elements.
