18 March 2013 23:38 [Source: ICIS news]
SAN ANTONIO, Texas (ICIS)--The advent of shale oil has caused many US refiners to examine processing tighter crudes, which could impact operations such as fluid catalytic cracker (FCC) units, a technology expert said on Monday.
An FCC unit uses high temperatures to crack crude oil hydrocarbons and convert them into olefins, gasoline and other products.
“Based our experiments, it is clear that FCC operations will shift and yields will shift,” said Chad Huovie, a product line manager at refinery technology licensor Honeywell UOP, during the American Fuel & Petrochemical Manufacturer (AFPM) annual meeting.
“The VGO [vacuum gas oil] and VR [vacuum residue] feed fraction from tight oil field production is hydrogen-rich, deficient in non-distillable carbon and contains minimal amounts of contaminants such as vanadium and nickel that cause issues in the operations of the FCC unit,” said the document by Honeywell UOP and refiner Marathon Petroleum.
“Although the quality of the tight oil is generally beneficial for FCC operations, the relative lack of non-distillable carbon residue will impact the FCC heat balance if run at high concentration,” it said.
Huovie said the impacts that shale crude processing will have on refinery balances and operations include increased gasoline-to-distillate ratios, as higher naphtha yields increase demands on the naphtha complex.
However, while the FCC feed quality improves with increases in gasoline selectivity and yields of light olefins, delta coke is reduced, which could create regenerator constraint.
In addition, the FCC regenerator temperatures are reduced, which will negatively impact coke combustion kinetics. That could mean higher emissions.
As a solution, Huovie said Honeywell UOP’s RxCat technology permits an improvement in regenerator emissions control and operation while increasing operating margin through higher throughput, conversion and/or improved yield selectivity.
He added that there are a number of solutions - including recycling slurry oil, utilising less coke-selective catalyst, increasing reactor pressure, reducing reactor stripper efficiency, firing the air pre-heater or adding torch oil to the regenerator - but all of those solutions will incur economic debit.
The AFPM annual meeting runs through Tuesday.
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