Title : The removal of refining hydrocracking’s heavy polynuclear aromatic hydrocarbons: Challenges and solutions
Heavy Poly Nuclear Aromatic (HPNA) hydrocarbon compounds are one of the major poisoning and corrosive substances that severely impact refinery equipment and catalyst life cycle. It is mostly produced as a by-product of the hydrocracking process, where the lack of efficient hydrogen contacts during the reaction phase results in the polymerization of the hydrocarbon as undesired products. Overtime-on-stream, HPNA formations increases exponentially and that forces refineries around the globe to adapt purging or bleeding techniques to reduce the HPNA concentration within the hydrocracking unit, which drastically impacts reactor conversion efficiency and product yields costing > $ 10 million per year. Currently, such operational mitigation approaches are contributing to additional amount of CO2 emission . In this work, we propose an alternative cost-efficient approach targeting reduction in carbon footprint, through the development of novel HPNA adsorption technology. The technology was designed for selective HPNA removal from Hydrocracker Bottom recycling stream having HPNA concentration of > 1000 PPM. Carbon based adsorbent was applied to demonstrate further selective performance for HPNA removal compared with commonly applied operational mitigation approches to illustrate the main limitations in currently applied approaches. We found that carbon-based adsorbents capable for HPNA removal. We concluded that carbon-based materials economically attractive by outlining the ideal scenario of HPNA removal through carbon-based adsorption process.