Fouling propensity of pyrolytic coke particles in aqueous phase: Thermal and spectral analysis

Agglomeration-deposition of pyrolytic coke particles has been assigned as the main concern of fouling formation of olefin units in heat exchangers, vessels, and towers. The aim of this study is to investigate the agglomeration and the fouling propensity of aliphatic-coated pyrolytic coke particles in the aqueous phase of quench water. Unusual surface properties of pyrolytic coke particles refer back to selective adsorption and formation of self-assembled monolayers of long-chain aliphatic hydrocarbons C-14-C(24)on the micropores of pyrolytic coke scaffold leading to formation of a thermal sensitive coating for agglomeration of suspended particles. Agglomeration of pyrolytic coke particles on solid surfaces was demonstrated using scanning electron microscopy (SEM) observations, and the morphology of fouling layer was studied. The experimental results revealed that the aliphatic coating, which encompasses about 40 wt% of the pyrolytic coke particles, is responsible for fouling propensity and particulate agglomeration of pyrolytic cokes in hot quench water. Thermal analysis as well as Fourier transform infrared spectroscopy (FT-IR) and energy-dispersive X-ray spectroscopy (EDS) spectra showed that adsorbed layer of hydrocarbons follows a first-order burning reaction and contains negligible amounts of heteroatoms, mainly aliphatic hydrocarbons.

Automated summary

The study focused on the agglomeration and fouling propensity of aliphatic-coated pyrolytic coke particles in quench water. It was found that the aliphatic coating, occupying about 40% of the pyrolytic coke particles by weight, is responsible for fouling and particle agglomeration in hot quench water.