Petrochemistry and Chemical Engineering

The build-up of undesirable materials on the surfaces of process units and heat exchangers, known as fouling, involves the deposition of solid or semi-solid chemical species present in the fluid that passes through the equipment, or the formation of chemical reaction products on the equipment surface. Coke fouling, a combination of these two fouling processes occurs in much of the equipment utilized throughout the industrial energy sector. Coke deposit composition is a complex element. Though, in general, coke is defined as carbonaceous material, this definition falls short in terms of the fouling process. The chemical and physical properties of the coke are highly dependent of the degree of hydrogen and oxygen inclusion, as well as the presence of heavy metals such as iron, vanadium, nickel and manganese. Over 60 different coke fouling samples, collected from various different refineries, upgraders and pipelines, were analyzed and found to have rather large variations in chemical composition and physical properties. Utilizing this information, a picture of coke fouling as a chemical spectrum begins to emerge, providing avenues for new and more effective methods for removing what continues to remain one of the largest fouling problems within the industry.