Low-Cost Protective Coatings for Increased Heat Exchanger Efficiency

Fouling occurs whenever gas or liquid flows through the pipes of heat exchangers, costing billions of dollars worldwide as well as increased energy use. If fouling were reduced, a corresponding reduction could be made in the heat exchanger surface area, providing more efficient heat transfer and enabling the use of lower-cost alloys as materials of construction. To address these fouling problems, this project will develop an ultra-thin, chemically-inert, glassy inorganic film of hermetic quality. The film, based on nanotechnology, will be deposited on the internal surfaces of heat exchanger tubes using a solution-derived, relatively low-cost, and high throughput process. In Phase I, coatings of this inorganic film will be deposited on two substrate materials and subjected to fouling tests under accelerated simulated conditions. In Phase II, one of the two substrates will be selected for further optimization of the coating and scale-up of process, in order to demonstrate the coating of tubular prototypes, as well as for testing in a production heat exchanger. Commercial Applications and other Benefits as described by the awardee: The nanotechnology coating technology should translate into reduced material use, improved efficiencies, and reduced maintenance, and should enable the use of lower grade alloys. The technology also should be applicable to a broad range of other fouling problems encountered in the oil, gas, and petrochemical refining industries. In addition, emerging opportunities in aerospace, automotive, fuel cells, and other renewable energy utilities should be candidates of opportunity.