According to Paragon Airheater, this new technology provides a longer life span of the heating element, improves or maintains the designed thermal performance of the surface configuration and it reduces emissions through its imbedded catalyst component.
In addition, the technology will improve the reliability and fuel efficiency of coal-fired power plants; especially in plants installing and operating new pollution control devices designed to reduce NOx emissions from coal-fired power plants.
DuraTec is a new nanotechnology tempered vitreous (porcelain) enamel coating that is applied onto the element sheets of the power plant’s regenerative airheaters. In coal-fired power plants, regenerative airheaters increase the efficiency of the plant (i.e. reduce coal consumption) by 10% to 15%, and for every ton of coal that is conserved, about 2.4 tons of the greenhouse gas CO2 is eliminated, the company said.
The element sheets inside an airheater act as heat sink that is used to preheat the air before it goes into the boiler to reduce the amount of fuel that is required for combustion. These element sheets can exceed one million square feet per power plant. DuraTec reduces airheater problems that are caused by the undesirable corrosive and fouling side effects of burning fossil fuels and the compounded side effects of operating NOx pollution control devices, the company claimed.
Since NOx is recognized as a pollutant associated with the formation of acid rain, most fossil fuel power plants already have, or will soon install, Selective Catalytic Reduction (SCR) systems as a post combustion method to reduce NOx emissions, Paragon Airheater said.
SCR’s operate by combining NOx with ammonia (NH3) in the presence of a catalyst to produce pure nitrogen (N2) and water (H2O). While effective in reducing the NOx emissions from power plants, the SCR process also reacts with the sulfur in coal to produce a byproduct, ammonium bisulfate (ABS), which has a detrimental effect on the efficiency and reliability of a critical fuel saving power plant component, the regenerative airheater.
John Guffre, chief research scientist of Paragon Airheater Technologies, said: ”The nanotechnology used in DuraTec – Tempered Enamel Coating was specifically developed for power plants equipped with SCR’s and the produced ABS byproduct. Using nanotechnology, the DuraTec coating provides an unparalleled non-stick surface texture to eliminate ABS deposition.
“Also, DuraTec’s patented formulation and proprietary thermally controlled multilayer applications result in four separate corrosion resistant layers on the airheater element surface to dramatically increase the life expectancy and durability of the airheater as compared to bare steel or traditional standard enamel.”
He added, ”The DuraTec coating can also be supplied with an SCR type catalyst imbedded onto the enamel surface of the airheater element. This additional catalyst layer is capable of cost effectively reducing the quantity of NOx emissions from a power plant beyond that of the SCR that is already in place.”
