Heat Transfer in Helically Coiled Tubes with Laminar Flow

Chemical Engineerin

Direct crude oil cracking for producing chemicals: Thermal cracking modeling

[EN] The direct cracking of crude oil is an interesting option for producing cheaply large amounts of petrochemicals. This may be carried out with catalyst and equipment similar to that of catalytic cracking, but at a temperature range between that of standard catalytic cracking and steam cracking. Thermal cracking will play a role in the conversion, but is rarely disclosed in experimental or modeling work. Thus, a crude oil and its fractions were thermally cracked and the products yields were modeled using a 9 lumps cracking scheme. It was found that heavy fraction cracks twice as fast as diesel fraction and ten times faster than gasoline fraction, with activation energies in the 140-200 kJ/mol range. Selectivity to ethylene, propylene and butenes were found similar in the operating range explored.The authors thank Saudi Aramco for its material and financial support. Financial support by the Spanish Government-MINECO through programs "Severo Ochoa" (SEV 2012-0267) and CTQ2015-70126-R and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Corma Canós, A.; Sauvanaud, LL.; Mathieu, Y.; Al-Bogami, S.; Bourane, A.; Al-Ghrami, M. (2018). Direct crude oil cracking for producing chemicals: Thermal cracking modeling. Fuel. 211:726-736. https://doi.org/10.1016/j.fuel.2017.09.099S72673621

INTEGRATING REFINING AND PETROCHEMICALS FEEDSTOCKS THROUGH A NOVEL FCC PROCESS

KFUPM has piloted a novel high-severity fluid catalytic cracking (HS-FCC) process that can increase the yield of light olefins to 40wt% of the product, versus the normal 10wt%. The process combines mechanical modifications with changes in process variables and catalyst formulations. The main operating regime of this novel refining process is high reaction temperature, short contact time, high catalyst/oil ratio and a special down-flow reactor system. The paper presents a brief experimental study on the cracking of vacuum gas oil using equilibrated FCC catalyst in a 0.1 bbl/d circulating downer pilot plant. The results show a significant increase in the yield of light olefins, mainly propylene, as well as an improvement in gasoline quality and overall conversion. By adding 10wt% ZSM-5 to the catalyst, the pilot plant yielded 18wt% each of propylene and butylenes or a total increase of 37% compared to base catalyst. A comparative economics of a base refinery (with a conventional FCC) and an upgraded refinery (with HS-FCC) is presented. About 28% of return on investment can be achieved for propylene and para-xylene recovery in the upgraded HS-FCC refinery