Crude distillation yields: Approximately what percentage (by volume) of straight-run gasoline is obtained from a typical crude oil without conversion processes?
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A6
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B18
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C38
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D52
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E28
Answer
Correct Answer: 18
Explanation
Introduction:“Straight-run” gasoline refers to the naphtha-range material obtained directly from atmospheric/vacuum distillation without catalytic or thermal conversion. The percentage varies with crude type but falls within a known range for typical crudes.
Given Data / Assumptions:
- Typical medium crude slate.
- Common refinery yield expectations prior to conversion.
Concept / Approach:Crude assays and textbook references commonly cite straight-run gasoline yields around 10–20% by volume for many crudes, often near the mid-teens. A representative figure in exam contexts is ~18%.
Step-by-Step Solution:
Eliminate extreme values: 38% or 52% are too high for straight-run without conversion.Very low 6% is possible for some heavy crudes but not “typical.”Select the canonical representative value: 18%.Verification / Alternative check:Assay tables for medium crudes show straight-run gasoline/naphtha near the high teens by volume.
Why Other Options Are Wrong:
- 6: Represents very heavy crude extremes.
- 38/52: Unrealistic for straight-run; such pool shares require conversion/upgrade.
- 28: Above typical straight-run ranges.
Common Pitfalls:Confusing the final gasoline pool (post-conversion blending) with straight-run naphtha.
Final Answer:18