Mitigate fouling to improve heat exchanger reliability. H.M. Joshi. Hydrocarbon Processing, January 1999, 78(1), 93--95.

Methods for improving the operational efficiency and cost effectiveness of refinery heat exchangers are recommended. Reasons for fouling and possible remedial actions are discussed. Hydrocarbon-related fouling is due to coking and polymerization reactions at temperatures exceeding 400 degrees F and is usually cured using mechanical brush-and-basket techniques. Corrosion-related related fouling by sulphur compounds occurs at temperatures above 550 degrees F and preventive measures include corrosion-resistant metallurgy and maintaining high velocities in the heat exchanger. Reboiler fouling is reduced by increasing the critical heat flux and this approach is described. Cooling water fouling is also discussed. Salt precipitation forms hard scale on the inside tube walls and silt deposition occurs if the flow velocity is too low.