How is the BMCI value of tail oil maintained in hydrocracking?
Thread Content
How is it ensured that the BMCI value of the tail oil remains within acceptable limits in hydrocracking? And how is the dry point of the heavy fractions controlled? Is this achieved by regulating certain parameters? Generally, is it done by combining analysis data with material balance calculations? Quick! ! ! !
For the BMCI value of the hydrotreating tail oil, in existing plants, it is only possible to adjust the reaction temperature, processing volume, or the amount of tail oil recycled. The control of the dry point of heavy naphtha depends on the top temperature of the distillation tower (since naphtha comes from the top of this tower); in addition, the feed temperature to the distillation tower and the amount of jet fuel extracted also have an impact.
In my opinion, the chemical approach to ensuring that the BMCI value meets the requirements is to retain straight-chain alkanes as much as possible and reduce their cracking reactions； Minimize alkane isomerization reactions ； Aromatic saturation, followed by ring opening, to minimize side chain cleavage ； Selective ring-opening of naphthenes, with retention of the alkyl side chains. In terms of catalysts, more new cracking catalysts should be developed to enhance their ring-opening selectivity and hydrogenation capabilities while suppressing their isomerization properties. That’s about all I know; I hope you can point out any shortcomings
The BMCI value for controlling tail oil is highly dependent on factors such as the type of unit, conversion rate, feedstock oil, and operating conditions. Additionally, it is highly related to the type of catalyst used. What was said on the 3rd floor is correct: the catalyst needs to have a strong ability to open rings as well as the capability to retain paraffins, in order to reduce the aromatic content in the tail oil. Retaining as much paraffin as possible helps to lower the BMCI value, thereby making the tail oil suitable as a feedstock for steam cracking to produce ethylene and increasing the yield of the three light hydrocarbons.