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Maximum diesel hydrocracking
Novel and innovative full-conversion process schemes.
With demand for diesel growing in key world markets and ever-more stringent product specifications, refiners are evaluating the technology options for the production of ultra-low-sulphur diesel (ULSD). Hydrocracking, an established and reliable method for transforming low-value heavy oil fractions into products with a higher value, is rapidly emerging as the principal conversion technology to maximise diesel yield.
By applying Shell Group (“Shell”) hydrocracking expertise gained from more than 35 years as a worldwide owner and operator, we offer cutting-edge technology licenses for new units and revamps. These technologies help refiners around the world to achieve the products and the performance they need in today’s marketplace and to meet ever-more stringent fuel-quality regulations.
About the technology
With a capacity of 512,000 bbl/d, Shell is the largest hydrocracker operator in the world. Shell Global Solutions provides technical support to over 50 sites worldwide. Since 2005, nine new hydrocracker licenses have been signed. We also have more than 60% of the hydroprocessing reactor internals market.
The extent of Shell’s operations gives clear insight into refining distressed crudes (those containing high nitrogen levels or with a high total acid number) and processing difficult hydrocracker feedstocks (those containing high nitrogen levels and having a high end point) while meeting ever-more demanding product specifications. Shell operates hydrocrackers processing a wide variety of feedstocks: coker gas oils, fluidised catalytic cracker (FCC ) cycle oils, deasphalted oils (DAO), thermally cracked distillates and hydroprocessed gas oils. Extradeep straight-run vacuum distillates with true boiling point (TBP) cut points of up to 590°C (TBP 90wt% of 570°C) are processed in several licensed units.
Figure 1: Low-cost heavy oil fractions are reacted with hydrogen at high temperature (350–450°C) and pressure (90–200 barg) in the presence of an optimised catalyst system to yield ULSD.
Shell Global Solutions provides pioneering hydrocracking configurations to help refiners respond cost effectively to the growing demand for ULSD.
Shell Global Solutions offers both single- and two-stage designs for full conversion hydrocracking to maximise diesel production. Each design is tailored to the type of feedstock, the capacity of the unit and the specific processing objectives to help optimise both capital and operating costs.
Our two-stage hydrocracker process configuration is best suited for large units and for processing difficult, high nitrogen feedstocks, and offers complete conversion of feedstock through two distinct reactor stages with intermediate fractionation. This helps to maximise the yield of high-quality products (kerosene and heavy diesel), see Figure 1 overleaf. Several other innovative process configurations are also available, including a single-stage design (once-through and recycle mode) to produce base oils or FCC or ethylene cracker feedstocks.
The hydrocracker technology is flexible enough to process a wide range of feed qualities of diverse origin at different conversion levels while producing on specification ULSD.
From industry studies covering unit performance from 1998 to 2006, a comparison of Shell hydrocracking units with the average industry performance shows clear and sustained advantages.
|Performance improvement compared with industry average|
|Turnaround duration||8-16 days|
|Source: 2006 benchmarking data|
Shell Global Solutions offers a commercially proven hydrocracker product work-up section that features a single main fractionator. This innovative configuration provides a 35–40% reduction in fractionation furnace energy consumption when compared with the conventional stripper–fractionator configuration.
Valero Energy Corporation
Valero, North America’s largest refiner, plans to construct a 50,000-bbl/d, unified-design hydrocracker at both its refineries in St Charles, Louisiana, and Port Arthur, Texas, USA, through an integrated contract framework with Shell Global Solutions and Criterion Catalysts & Technologies. The deliverables will include access to Shell Global Solutions’ licensed technology and know-how; a complete design solution; reactor internals; Criterion catalysts; a customised process model; operational staff training; commissioning and start-up assistance; and unit optimisation.
Mariisky NPZ LLC
Mariisky plans to upgrade and expand its refinery in Mari El Republic, Russian Federation, to meet the Euro V diesel fuel specification and maximise the production of light, high-value products. The first phase will include the construction of a hydrocracker designed to process a feed blend of vacuum gas oil and DAO at over 90% conversion to maximise the production of high-quality diesel. Shell Global Solutions is supplying basic design packages and process unit licences.
Our hydrocracking technology and expertise offer a range of commercial benefits:
- technical services and advice on unit optimisation that help refiners to meet fluctuating market demands and changing legislation;
- access to catalysts that are designed to provide improvements in yield and stability, and activity advantages; and
- integrated life-cycle catalyst services and advice.