Seeking help with hydrocracking issues

I’ve never heard of this issue; it doesn’t seem to matter whether it’s high or low, right? I don’t think there’s any difference I’m not sure what the impact will be on the engineering side; it makes no difference from a process perspective

Not necessarily; it depends on the properties of the raw materials, the properties of the product, and the performance of the catalyst.

In a hydrocracking unit, the height of the refining reactor does not necessarily have to be greater than that of the cracking reactor; it is sufficient as long as the amount of refining catalyst and the pressure drop meet the process requirements.

Not necessarily. The optimal reaction temperature is primarily determined by the nitrogen content in the refined reaction products; catalyst suppliers specify requirements, usually requiring it to be no more than 20 ppm. The nitrogen content in the feed oil, hydrogen partial pressure, hydrogen-to-oil ratio, and space velocity all have an impact. The cracking reaction temperature depends mainly on the conversion rate you desire, as well as the yield of the desired product. Good matching control is essential; the two temperatures should be similar. If one temperature is significantly higher than the other, it will lead to a situation where one component reaches the end of its useful life while the other can still be used for another year – which is a loss in terms of efficiency. This post was last edited by net2002163 on 2009-2-13 21:06.]

Not necessarily; our first reaction yield is slightly lower than that of the second reaction, and this is also determined by the properties of the catalyst. There are design requirements, so there’s no need to be too precise about it.

The size of the reactor can be determined only by considering the properties of the raw materials and deciding on the amount of catalyst to use.

Check the requirements for the n content in the refined oil, as well as the Sn content in the raw materials. If the Sn content in the raw materials is high, then the reaction temperature will definitely be high; consider the design requirements

I think the key is to look at the catalyst

The bed height for hydrogenation refining in our plant is higher than that for hydrocracking; however, there are also records indicating the opposite. In my opinion, the following factors play a role: 1. The levels of elements such as N, S, Cl, O, and Fe in the crude oil; 2. The quality of the refining catalysts; 3. The properties of the feed oil

The main reason for this issue, which also poses difficulties in the development and application of hydrocracking, is the bottleneck associated with expanding the capacity of existing hydrocracking units or enabling their operation over long periods of time – namely, the insufficient capacity for raw material pretreatment, or in other words, the limited nitrogen removal capability. In a typical sequential process flow, the space velocity for pre-refining is 0.8–1.2 h-1, while the space velocity for cracking can reach 1.5–2.6 h-1. As a result, reactors need to be designed with larger units for pre-refining and smaller ones for cracking, and this process flow is used in the vast majority of cases in China. However, there are exceptions; for instance, the hydrocracking units in Jinling and Hainan use an FDC single-stage process flow, so strict requirements are not imposed on the nitrogen content at the refined nitrogen outlet. These units focus primarily on the cracking reaction stage in order to produce the largest amount of intermediate distillate oil. Their reactor design is the opposite of that of the previous type – with less refining and more cracking. It seems that Jinxi and Liaohua also use this process flow; it would be a good opportunity to see it in person.