2 replies to this topic

[rajarshi2016]

Hi,

 

Can someone please elaborate me the differences between a mild hydrocracker and a normal hydrocracker?

 

Regards,

Rajarshi

[Profe]

Hi Rajarshi

Try first at refining textbooks.

From: Petroleum Refining - Technology and Economics 4th ed - J Gary, G Handwerk -Marcel Dekker. Pages 153 and 154

Modes of hydrocracker operation

Full-conversion hydrocracking operations are very expensive in terms of both original capital cost and direct operating cost because of the high pressures at which the units operate [1800–2500 psig (120–170 barg)]. As a result, units designed to operate at lower pressures are being used to obtain some of the benefits of hydrocracking at lower costs. These units are called mild hydrocracking(MHC) units or moderate pressure hydrocracking (MPHC) units. UOP refers tothe MPHC units as partial-conversion units [19]. The MHC units operate at pressures in the range of 800–1200 psig (55–82 barg) and the MPHC units at pressures in the range 1400–1500 psig (95–102 barg).

The MHC units are frequently used to reduce the sulfur and nitrogen contents of fluid catalytic cracking unit feedstocks while also increasing the amount of middle distillate fuel (diesel) blending stocks. Yields of up to 30% full-range diesel fuel with cetane indices between 30 and 40 can be produced from virgin vacuum gas-oil feedstocks [20].

The MPHC units, operating at higher pressures and costing from 1.5 to 1.8 times the cost of a MHC unit, can produce from 35–40% full-range diesel blending stocks with cetane indices of 45–50. They can also be operated to produce 10–20% kerosine blending stocks with smoke points of 15–20 [19].

The MHC and MPHC units offer refineries the flexibility of producing higher yields of high-quality middle distillate products with capital and operatingcosts from 50–80% of those of a full-conversion hydrocracker.

 

thanks to J Gary, G Handwerk

 

Good luck

Fausto

[rajarshi2016]

Thank you