9. Two possibilities for replacing, or at least supplementing, petroleum when it becomes in short supply are syncrude produced from the Athabasca oil sands in Canada, or oil liberated from the oil shale in the Rocky Mountains in the U.S. A major concern for any refinery engineer is the hydrogen requirement for hydrotreating, because hydrogen is expensive. The table below compares typical compositions of shale oil, syncrude, and a 31 API Oklahoma crude (petroleum). (a) If you were the refinery engineer, and were given a choice among these feedstocks, strictly from the perspective of hydrogen requirements for the hydrotreaters, indicate which would be your preferred choice, and which you'd prefer to avoid. (b) Explain why. It is not necessary to do any new calculations for this problem but explain your answer in the context of what you learned about hydrogen requirements for HDS and HDN. Sample %C %H %N %S Green River Oil Shale Oil 84.6 11.5 2.0 0.6 Athabasca Synthetic Crude Oil 85.9 11.8 0.4 1.6 Oklahoma 31 Crude 85.7 13.1 0.3 0.4