Reduction of Coke Accumulation and Energy Resources by Adding Steam and Carbon Dioxide in Naphtha Based Ethylene Production

In this study, the production of ethylene and hydrogen is studied via the thermal cracking of ethylene in an ethylene plant based in Libya. During the process of thermal cracking, a mix of naphtha and steam is input into tubes that are directed to the naphtha main line. The utilization of steam is generally used because of the partial removal of coke which has undesirable effects on the process. The coke accumulation on the coils, or tubes, result in a decrease in pressure and also reduction in the yields produced. In this work, the naphtha thermal cracking process is both designed and solved numerically. A thorough comparison of the design results and the data extracted from the experiment reveal that the design may predict the overall process precisely. Also, the direct effects of CO2 are studied with regard to the accumulation of coke. Based on the results of two separate scenarios, the process of thermal cracking with the CO2 is beneficial to the overall process due to the higher yield of ethylene and propylene, and less accumulation of coke, and, in turn, less thickness on the coils inside the furnace. The results from the simulation show that the run time, or run length, of the furnace with the addition of CO2 becomes almost two times as the run time with adding steam. Based on these results, this study has proven to be worthy to explore, and the addition of CO2 has been observed to have noticeably positive results on the thermal cracking process. Keywords: naphtha, ethylene, hydrogen, coke accumulation