The first thermal cracking processes were developed in 1913 with the purpose of heating atmospheric tower residues and heavy gas oils until the molecules cracked and broke apart.¹ The reason for conducting this process was to break up the less desirable petroleum products and form them into highly valuable light middle distillates such as naphtha, gasoline, and diesel fuel among others². Thermal cracking became incredibly important with the invention of the automobile which uses an internal combustion engine fired by diesel or gasoline. With more people driving, the demand for fuel skyrocketed and the cracking process made it possible to produce more gasoline and diesel than was produced from crude oil as a straight run product³. For twenty to thirty years it was the pinnacle of petroleum refining processes, however by the start of World War II thermal cracking could no longer generate the quantity or quality that was demanded. At this time automobiles and planes required higher octane fuels that simply are not capable of being produced from the simple brute force cracking process¹. Instead, a new process called catalytic cracking was introduced which was capable of yielding larger amounts of higher quality fuel. While limited in use, thermal cracking is still used today with its primary roles being the production of diesel fuel and ethylene².

1. “Petroleum Refining Process.” Petroleum Refining Process. N.p., n.d. Web. 26 June 2014. <http://www.ilo.org/oshenc/part-xii/oil-and-natural-gas/item/384-petroleum-refining-process>.
2. Semih, Eser. “Lesson 6: Thermal Conversion Processes.” FSC 432: Petroleum Processing. N.p., n.d. Web. 28 June 2014. <https://www.e-education.psu.edu/fsc432/content/lesson-6-thermal-conversion-processes>.
3. Solomon, Lee. “Visbreaking, thermal cracking, and coking.” Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 28 June 2014. <http://www.britannica.com/EBchecked/topic/454440/petroleum-refining/81801/Visbreaking-thermal-cracking-and-coking>.