Does an increase in the composition of the hydrocracking feed leading to a heavier mixture result in a larger temperature difference across the reactor catalyst bed?
Thread Content
Does an increase in the composition of the hydrocracking feed leading to a heavier mixture result in a larger temperature difference across the reactor catalyst bed?
Yes, variations in the raw materials naturally lead to an increase in the sulfur, nitrogen, and oxygen content in those materials, thereby increasing the heat released during the reaction； Variations in the raw materials naturally lead to an intensified cracking reaction and an increased hydrogenation reaction, along with heat release ； Therefore, the temperature rise will increase in both the refining and cracking sections.
Reply to 2# jiang_ry: When the raw material becomes heavier, the olefin content decreases, and hydrogenation of olefins releases the most heat. The raw materials become heavier, the content of impurities such as S and N increases, and the reaction conditions become more stringent, which requires raising the temperature. It can be seen from the first refined bed layer that the temperature difference in both cases has increased.
The feedstock for hydrocracking is mainly straight-run wax oil, and even the amount of secondary wax oil and diesel produced is not significant. So as the raw material becomes heavier, olefins should not be taken into consideration.
Reply to 4# jiang_ry: This is a skill assessment question; the answer is to become smaller. I don’t quite understand it. Actually, I had observed this on DCS before: in the first refining bed layer, no cryogenic hydrogen was used, so it’s easiest to see the temperature rise situation. When the raw material becomes lighter, there is a temperature rise; the same is true when it becomes heavier. Therefore, it is not possible to determine whether the raw material has become lighter or heavier based solely on the bed temperature rise.