Coke Inhibition During Naphtha Pyrolysis

The effectiveness of binary mixtures of phosphorus and sulfur compounds as coke inhibitors for naphtha pyrolysis has been studied. As both phosphorus and sulfur compounds proved to be promising coke inhibitors, runs were made with mixtures of these compounds. The coke deposited was significantly lower when phosphor was used together with sulfur. Also, the effect of the addition of Na2CO3 and K2CO3 in the naphtha feed was investigated. It was found that the addition of Na2CO3 and K2CO3 reduced the coke formation. Scanning electron microscope (SEM) was used for the microstructure of deposited coke and energy dispersive X-Ray spectroscopy (EDAX) for the surface elemental composition of coke formed on the surface of stainless steel coupons. It was found that in the presence of inhibitors, deposited coke has a porous structure and so small amounts of Ni , Cr , and Fe elements.