Petroleum Refinery Engineering MCQ Questions & Answers | Chemical Engineering

The correct answer is B: Vacuum residue.
Here's why:

Coking is a process that uses heat to break down large, heavy hydrocarbon molecules into smaller, lighter ones and solid carbon (coke).

Vacuum residue is the heaviest fraction remaining after vacuum distillation of crude oil.
It contains the largest and most complex molecules, making it the most suitable feedstock for coking.

Let's look at the other options:

Naphtha, Light gas oil and Diesel are all relatively lighter fractions with smaller molecules.
They do not contain enough of the heavy components required for efficient coke production.
These fractions are generally used as gasoline, diesel fuel, and heating oil.

Therefore, vacuum residue is the most ideal feed for coking because it maximizes coke production.

In petroleum refinery engineering, the water content in crude oil as it comes out of the oil well may be as high as 25 percent (Option D).

Crude oil extracted from oil wells often contains various impurities, including water, sediments, and gases. The water content in crude oil can vary depending on factors such as the geological formation of the oil reservoir and the methods used for oil extraction. In some cases, crude oil may contain significant amounts of water, up to 25 percent or more, which needs to be separated and removed during the refining process.

Therefore, the correct option is Option D: 25.