Coke formation mechanisms and coke inhibiting methods in pyrolysis furnaces

Research has been carried out to understand the mechanisms under which coke formation occurs and to search for solutions to reduce or eliminate coke deposition. Significant efforts have been exerted over the past twenty years in developing coke-inhibiting methods. Coke inhibitors, i.e., chemical additives, or special coating of metal surfaces which suppress coke formation. Coke inhibitors/surface coating work by passivating catalytically active metal sites through chemical bonding interactions, and/or forming a thin layer to physically isolate the metal sites from coke precursors in a process stream, and/or interfering with those radical reactions leading to coke formation by blocking active radical sites on surfaces. This review paper investigates the effect of the most important methods such as new chemical additives, tube material construction, pretreatment of surface on the coke formation of pyrolysis furnaces.