Catalytic cracking external slurry

The slurry discharged from the catalytic unit contains, first, a certain amount of catalyst, and second, a high proportion of polycyclic hydrocarbons; its specific gravity is generally greater than 1. When the solid content of the slurry is too high, oil separation is carried out to stabilize its solid content and prevent blockages in pipelines and equipment. Under normal circumstances, due to the high content of condensed ring hydrocarbons in the slurry, its cracking performance is poor and the coking rate is high; by removing an appropriate amount of this slurry, a better product distribution can be maintained. The externally discharged slurry has various uses; one of them is to be mixed into heavy fuel oil, and this is a common practice ； Secondly, transferring it to the propylene deasphalting unit in the reduced-pressure residue stream can increase the yield of deasphalted oil, and at the same time improve performance parameters such as the ductility of the semi-asphalt ； Thirdly, after the oil slurry is clarified, it can be fed into the furfural unit (where a composite solvent may be required) for extraction and separation. The oil obtained through this process remains an excellent catalyst precursor, while the residue oil has a higher aromatic content and can be used as a rubber filler oil; it is said to can also be utilized in the production of carbon fibers.

In heavy oil catalytic cracking, it is generally necessary to remove the slurry from the process; this slurry contains a high amount of polycyclic aromatic hydrocarbons, which results in significant coke formation. Reducing the amount of slurry that is recycled can help minimize coke production and prevent the regenerator from overheating and damaging the equipment. In our unit’s catalytic reactor, 60% of the slag is incorporated, with 4–5% being discharged. The external slurry can be fed into a slurry filter, where the catalyst powder is separated out and serves as an excellent raw material for hydrocracking, hydrodesulfurization, and the production of needle coke via coking

3# wangrennan1984 I’ve read in some literature that the filtration methods used in current catalytic cracking slurry dewatering devices aren’t yet widely adopted in China! It’s mainly the solvent dehydration method; why does your factory have equipment for filtration-based dehydration? Moreover, most of the equipment imported into China from abroad is essentially useless.

As far as I know, oil slurry filters in China are still in the development stage, and it may take some time before they can be used on an industrial scale; it seems that tests are being conducted in Jiujiang. Abroad, there are methods that can reduce the catalyst level to below 100 ppm.

I had previously seen some methods for removing catalysts from slurry oils, but I have not heard of any equipment for treating such slurry oils in local refineries.

1. The slurry can be extracted using solvents. 2. It can be used as a raw material for coking

2# zhonghe998 Saccharaldehyde plant – please explain it, thank you

The catalytic slurry produced by our factory is used as a feedstock for delayed coking, and it is an excellent material for producing needle coke

Entering delayed coking seems to be a reasonable option; there is some waste of fuel oil, so it can be mixed in and reused in refining