May I ask under what circumstances is ARDS used in the oil refining process, and when is VRDS employed?
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ARDS: Common residues include depressurized wax oil without hydrodesulfurization； Why is vacuum paraffin oil not hydrogenated or catalytically cracked separately?
Wax oil has high sulfur and nitrogen contents; if it is used directly in catalytic processes, the resulting gasoline and diesel do not meet the National III standards. After hydrogenation, the sulfur and nitrogen contents in wax oil are significantly reduced. Through catalytic cracking, the sulfur content can be further reduced to 1/10 to 1/20 of its original level, thereby meeting the National III standards. The hydrogenation unit for wax oil is designed to produce high-quality feedstock for catalytic cracking, by removing ammonia, nitrogen, sulfur, and metals from the wax oil. The main hydrogenation feedstock is coker wax oil. Straight-run vacuum wax oils S and N have low levels of basic and non-basic nitrogen, so hydrogenation is not required.
With the adoption of the National V standard, vacuum wax oil has begun to be fed directly into hydrocracking units; the unit where I work uses a mixture of straight-run wax oil and coker wax oil as feedstock
Could someone introduce the Dalian West Pacific process? Why use ARDS? Instead of VGO being used for catalysis or hydrocracking, should the alkaline sludge be used in VRDS?
The online rate of RDS is not high, and the investment required is substantial; is it worthwhile to use VGO in ARDS?
VRDS should be a suitable option; after controlling the solid content in the catalytic slurry, it can be fed into the residue hydrogenation process. The oil resulting from residue hydrogenation can then be fed back into the catalytic process, which yields excellent results. Black products are also the fewest.
Can it be understood this way: earlier on, ARDS was used because VRDS technology was not yet mature enough (since VR has higher Ni+V levels and more residue compared to AR)? If it were done today, Dalian Xitai would not use ARDS either; instead, would it use VRDS?
Reduced-pressure wax oil can be fed directly into hydrocracking units. In the past, catalytic cracking was the preferred method due to the high requirements for oil quality, which is why most units were built for catalytic cracking. Now, with even higher demands on oil quality, hydrocracking has become more popular