ABSTRACT
This chapter presents a description of the concept of fouling in refineries which can occur as deposit formation, encrustation, deposition, scaling, scale formation, slagging, and sludge formation), all of which can have an adverse effect on refinery operations. It is the accumulation of unwanted material within a processing unit or on the solid surfaces of the unit to the detriment of function. For example, when fouling does occur during refinery operations, the major effects include (1) loss of heat transfer as indicated by charge outlet temperature decrease and pressure drop increase, (2) blocked process pipes, (3) under-deposit corrosion and pollution, and (4) localized hot spots in reactors, all of which culminate in production losses and even refinery shutdown. Thus, the separation of solids occurs whenever the solvent characteristics of the liquid phase are no longer adequate to maintain polar and/or high molecular weight material in solution.
