The hydrocracking unit temporarily needs to process low-sulfur oil; what is the ratio of low-sulfur oil to high-sulfur oil, and which type yields lighter components more easily?

Following up, could you explain the basis for this? Experience or mechanism

It depends on the properties of the crude oil; it seems to have little to do with whether the crude oil contains high or low levels of sulfur.

Under normal conditions, the properties of low-sulfur oil are lower in terms of specific gravity, nitrogen content, and metal content, right? ! If that’s the case, then would it become relevant?

In my opinion, high-sulfur oils require harsh reaction conditions and high temperatures, which increase the likelihood of the formation of light components.

It is mainly related to the density of the crude oil; fewer of the heavier components are produced, while more of the lighter components are formed. The temperature rise in the high-sulfur oil reactor will be higher.

I believe it mainly depends on the properties of the raw materials and the selectivity of the catalyst

The amount of light components produced is related to the reaction temperature, reaction pressure, catalyst activity, and the composition of the feedstocks, and it has no direct relationship with the sulfur content.

Thank you all, experts! :lol

It seems to have little to do with whether the sulfur content in crude oil is high or low; it mainly depends on factors such as the hydrocarbon composition, boiling range, and the density of the raw material

Compared to processing low-sulfur crude oils, the reaction parameters change significantly when processing high-sulfur crude oils. (1) Under the same load, to ensure a certain desulfurization and denitrification rate, it is necessary to increase the inlet temperature of the reactor, which leads to an increase in the average temperature of the reactor. An elevated reaction temperature for the catalyst inevitably shortens its lifespan. (2) As the sulfur content in the device increases, the amount of cold hydrogen required rises; the amount of cold hydrogen used between the refining and cracking reactors also increases. With a constant outlet capacity, this increase in cold hydrogen consumption leads to a decrease in the amount of circulating hydrogen, thereby reducing the hydrogen-to-oil ratio at the inlet of the refining reactor. (3) A significant increase in the sulfur content of the crude oil leads to a decrease in the purity of the recycle hydrogen. Since hydrocracking units do not have facilities for desulfurizing recycle hydrogen, in order to maintain the required concentration of recycle hydrogen, it may be necessary to frequently discharge high-sulfur recycle hydrogen. (4) As the sulfur content in the crude oil increases, the iron ion content also rises, which leads to an increase in the pressure drop across the bed in the refining reactor. (5) Since the opening degree of the cold hydrogen valve in the first bed of the cracking reactor is relatively high during normal operation, the increase in the average reaction temperature of the reactor leads to higher H2 consumption; accordingly, the opening degree of the cold hydrogen valve must be increased as well. This results in no room for adjustment of the cold hydrogen valve in the first bed of the cracking reactor, posing a risk to the safe operation of the plant. Based on these criteria, there should be more light components with high sulfur content