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Hydrocracking
Axens hydrocracking
Excellence from innovation and experience
Processes, catalysts and services
World oil demand is primarily driven by the transportation fuelssector. Forecasts show significant growth in these fuels, while theshare of heavy fuel oil will decrease in the refined products slate.Among fuels, on-road diesel and jet fuel will exhibit the highestgrowth rates, about 2.5% per year over the period 20102020.Along with this trend, fuel specifications continue to be tightened,pushing demand towards ultra-low-sulfur, low-polyaromatics-content, high-cetane diesel.
Hydrocracking technology can respond to the most demandingmarket constraints. This flexible process is capable of converting awide variety of feedstocks into diesel and jet fuel products thatmeet the most challenging specifications. For cases whereincomplete conversion is desired, the unconverted hydrocrackedresidue (also called unconverted oil, UCO) can, because of itsexcellent properties, be used as a high-viscosity-index (VI) lube oilbase stock, as a superior steam cracker feedstock owing to its verylow BMCI* value or as an FCC feed.
High price differentials between on-road diesel/jet fuel andhydrocracking feedstocks encourage investment in hydrocrackingunits owing to high profitability and short payback times.
* BMCI: Bureau of Mines Correlation Index
Axens is an established name in hydrocracking licensing with morethan 40 years experience in all types of hydrocracking processes.
We have a large portfolio of hydroconversion processes, includingfixed- and ebullated-bed technologies. Our commercial unitsoperate at low, medium and high conversion, and in once-through, single-stage recycle and two-stage modes.
As of 2011, Axens hydrocracking technologies had been selectedfor more than 80 licensed units with a combined capacity of over3.3 MMBPSD.
Axens has a global reputation for basic engineering designexcellence. We provide both limited and extended basicengineering packages and can extend this capability upon request.
Our technical services are second to none, and include theprovision of training, catalyst loading, start-up assistance,performance monitoring, troubleshooting and processoptimization.
Conventionalcrude VGO
High-gradediesel, jet fuel
+high-VI lube
oil basesor
FCC, SC feeds
Heavy crudeVGO
Coker VGO
Visbreaker VGO
VGO ex-resid HC
DAO
Lube by-products: aromatic extracts,
paraffins
LCO, HCO
The considerable flexibility available with these technologies isenhanced by a complete line of dedicated materials covering feedpretreatment and conversion steps. Applying the right combinationof materials and process designs enables our technology torespond to a diverse set of economic and operational constraintswith various feedstocks, desired conversion levels and productselectivities. Hydrocracking objectives are achieved while ensuringlong catalyst cycle lengths and employing best practices relating tooperational, environmental and safety concerns.
Our commercial hydrocracker designs can cover a large variety offeedstocks varying from light HGO and LVGO feeds to the mostdifficult feeds, such as highly resinous and organic-nitrogen-containing VGO, processed VGO or DAO. In addition, ourhydrocracker designs are exceptionally adapted for upgrading low-quality products such as LCO, which is used as a cutter stock forheavy fuel oil. With the continuing decrease in demand for heavyfuel oil, additional low-cost LCO will be available for upgrading.
Rec
om
men
ded
hyd
rocr
acki
ng
pro
cess
H-OilDC, mild hydrocracker + guard bed
MHC, HyC-10
HGO, LVGO VGO, HCGO, LCODAO-C3, C4
Refractory VGODAO-C4, C5
Hytail Incre
asing
resis
tance
to hy
dropro
cessin
g
HyKone-stage(once-through or recycle)two-stage
Mid
dle
dis
tilla
te s
elec
tivi
ty
Activity
Alumina
Amorphous
Low-acidityzeolite
High-acidityzeolite
Axens technologies cover every type of feed A wide range of catalysts is available to meet specific market objectives
Mild hydrocracking and HyC-10
For refineries equipped with a VGO FCC unit, mild hydrocracking(MHC) enables increased diesel production through VGOhydroconversion. This process simultaneously improves the qualityof the treated VGO, which, once converted in the FCC unit, offershigher gasoline yields, higher octane retention, lower SOxemissions and lower-sulfur products. Under conventional MHCoperating conditions (low-to-medium pressure range, 50100 bar[7301500 psi] and 2040% conversion levels) direct productionof 10-ppm-sulfur diesel is not easily attained. Axens commerciallyproven HyC-10 technology achieves both objectives, therebyenabling diesel cut quality to be controlled independently from theVGO conversion. This has the added advantage of not puttingexcess hydrogen into the treated VGO and reducing theinvestment costs.
In addition, HyC-10 systems can be designed to co-process otherdifficult feedstocks present in the refinery such as LCO, lightcracked GO, and visbroken GO. Streams like these can exhibit highmetal or CCR values, which shorten run cycles. Axens permutableguard reactors can be installed to counteract this problem.
H2
VGO
Lights,naphtha
Low-sulfurVGO
10-ppm-sulfur
diesel tostripping
Diesel fromCDU, FCC, VB,
coker, etc.
LsV
Prime-DHDT
HyC-10 mild hydrocracking scheme
High-conversion hydrocracking (HyK)
To achieve conversion levels higher than 50% and to maximizemiddle distillate production from VGO and light DAO, Axens offersthree configurations of HyK processes: single-stage once-through,single-stage with liquid recycle, and two-stage. All thehydrocracked products, including unconverted oil (UCO), presentexcellent characteristics.
The configuration selected will depend on the desired productslate and the investment criteria. For instance, when thehydrocracking project is driven by a high diesel incentive, a two-stage full-conversion scheme provides maximum production ofexceptional-quality diesel.
Single-stage once-through hydrocracker
Two-stage hydrocracking scheme
Hydrotreatment
Naphtha
FG+LPG
H2
Feed Hydrocracking
Hydrocracking
H2
H2
Kerosene
Diesel
Bleed
H-OilDC
For the most refractory feeds, including heavy VGO and DAO-containing feeds, the H-OilDC ebullated-bed technology is suitablefor deep-conversion objectives. Conversion levels of over 80% areachievable by adjusting operating temperature, residence time andcatalyst replacement rate. Recycling of unconverted VR to a solventdeasphalting unit enables nearly full conversion of the DAO. Theaddition of an integrated hydrotreater on the H-OilDC distillatefraction ensures ultra-low-sulfur-diesel quality.
H-OilDC and Solvahl (solvent deasphalting) combine for nearly 100%
conversion of heavy DAO
SolvahlC4C5
VR DAOLight ends
H-OilDC
H2
Asphalt pitch
Recycled VR
VGO
GasolineDieselVGO
Our new-generation commercial hydrocracking catalysts treat awide range of feeds to produce a diverse slate of products thatrespond to specific quality targets.
For high conversion hydrocracking applications, the combination ofHRK, HDK and HYK series is definitely the best solution to squeezemore middle distillates from heavy ends while reaching highconversion levels.
A once-through HyK hydrocracker operating with straight-runVGO at 80% conversion (see figure right) would typically beloaded with: several sets of EquiFlow reactor internals; different ACT materials; HF / HMC Series demetallization catalyst; the winning combination of HRK Series + HDK Series + HYKSeries and;
HR Series catalyst to ensure optimal product quality.
Grading materials and reactor internals
For fixed-bed hydrocracking processes, ultimate performance ofthe technology begins with feed pretreatment and a design thatprovides near-perfect liquidgas distribution throughout theprocess.
Axens EquiFlow reactor internals are designed and commerciallyproven to provide the industrys best fluid distribution. This ensuresthat the entire catalyst inventory is used uniformly and that thelongest catalyst cycles are attained.
Once the hydrodynamic design is established, the next step is toensure that undesirable feed materials, such as scale, polymer,other entrained solids, and highly reactive molecules do notprematurely end the operation cycle through pressure drop build-up, catalyst plugging or deactivation. To reduce the effect of thistype of frequent problem, the top bed of the unit is loaded withACT series grading materials that vary from non-porous to porous,large to small and low to high activity. Depending on the metalscontent (V + Ni) in the feed, the addition of Axens HF & HMCSeries demetallization catalysts may be required before contactwith the pretreatment catalyst to ensure long cycle lengths.
The cleaned, uniformly distributed feedstock and hydrogen arenow in the optimum condition to be catalytically hydrotreated toremove sulfur and nitrogen and then hydrocracked into lighterproducts.
High-conversion hydrocracking application
The HRK Series hydrotreating catalyst features very highdenitrogenation activity while affording deep sulfur andaromatics removal.
HDK Series fills