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Across the industry, there are numerous recent examples of large refinery projects stalling at the front-end engineering and design phase, as their costs spiralled out of control or financing became difficult. Nevertheless, several multibillion-dollar hydrocracking projects have been delivered successfully. Here, hydrocracking technology and catalyst experts discuss some of the insights gleaned from recent projects that may help to make projects viable in the current economic climate.

Infographic showing the anatomy of successful projects in Shell Global Solutions' HCP supplement

Because of the substantial return on freed capital, there is an argument for investing the cash generated by Pentagon I in revamps – Pentagon II. These can help to further improve margins, helping to fund a phased investment programme – Pentagon III.

1. Phase the investment: The pentagon model

While the global economic upturn continues to gain momentum, many refiners are still finding themselves short of cash and securing the financing for new projects can be testing. That is why Süleyman Özmen, Vice President, Refining and Chemical Licensing, Shell Global Solutions International BV, proposes a three-pronged strategy for when refiners are planning an investment – the multiplatform pentagon model.

"Pentagon I advocates a focus on operational improvements such as reliability and energy management projects that do not require capital expenditure," he says. "These are short-term initiatives and can help to fund Pentagon II initiatives, which are short-to-medium-term revamp solutions. In turn, the cash generated from those initiatives can be used for larger, more-capital intensive projects of Pentagon III." Each of the three pentagons has investment options on all five sides.

Hydrocracker-related projects are fundamental to this model, as is the Shell Sulphur Technology Platform.

Designed to help refiners process heavier, sourer crudes, while meeting stringent emissions and product requirements, the Shell Sulphur Technology Platform is a portfolio of integrated, comprehensive technology solutions customised to meet a refiner’s specific needs. It includes technologies from carefully selected key companies to manage sulphur in various forms, including sulphur in crude; sulphur in products; hydrogen sulphide; sulphur dioxide; mercaptans; and solid sulphur.

Key truth: High-performing companies are enhancing the viability of major projects by phasing their investment programmes. They are using the cash generated by low-cost projects to fund larger, more-capital-intensive projects.

2. Leverage economies of scale

Maximising the capacity of each train can help to bring capital expenditure down, says Nicolaas van Dijk, Global Process Technology Manager, Hydroprocessing, Shell Global Solutions International BV. But, he says, it is vital for the licensor to be able to demonstrate that such capacities are achievable.

"To enhance the economics of CNOOC’s new hydrocracker, we suggested during the development phase that they could achieve the same capacity from two trains instead of three," he says. "That brought the cost down significantly, but an important element of their decision making was that we were able to show them another site, the Shell Pernis refinery in the Netherlands, successfully operating a hydrocracker with similarly sized trains."

Key truth: Economies of scale can substantially enhance project economics – but reference sites should always be studied.

3. Make maximum use of existing equipment: Integrate solutions

One of the most effective ways to reduce investment costs is the intelligent integration of process units, writes Yvonne Lucas, Licensing Technology Manager, Refining, Shell Global Solutions International BV.

"One customer in Europe wanted to build a mild hydrocracker complex to process a mix of medium and heavy VGO, and also hydrotreat the gasoil from a crude distiller," Lucas explains. "We could have offered two separate standard designs. Instead, to squeeze down the capital cost, we designed an integrated reactor section: the hydrodesulphurisation (HDS) reactor and the hydrocracking reactor were combined with a common separation, compression and fractionation section. Because the customer only needed one unit instead of two, the capital cost was significantly reduced."

Key truth: Designs should make maximum use of existing equipment. Integration with other process units can help to keep costs down.

4. Optimise the conversion level

The greater the level of conversion, the greater the capital expenditure required. Mike Street, Hydroprocessing Principal Process Engineer, Shell Global Solutions International BV, says the licensor’s objective should be to find the conversion sweet spot, which is strongly affected by the properties of the feed.

He explains, "In recent projects, we have configured the hydrocracking processes in such a way that the capital cost is balanced against the potential margin. Along with the future licensee, we work hard to closely integrate the new hardware into the rest of the refinery. Designs that are based on partial conversion of the feedstock manage the capital cost of the hydrocracker better, integrate more effectively within the refinery and can produce an excellent return on investment."

Street continues, "Total conversion, or anything approaching that, is too expensive for many refiners in today's market. There are projects that went after 98% conversion but that required such huge reactors and catalyst volumes that the cost became unmanageable."

Key truth: Designs should find the conversion sweet spot. For relatively tough feeds this is typically at a 60–80% conversion level, as long as integration with other units is possible. This can be an effective way to manage the cost and still provide a reasonable refining margin.

5. Consider the sulphur balance; manage the bottom of the barrel

Although there are robust technologies, such as KBR's Residuum Oil Supercritical Extraction (ROSE) unit, for preparing high-quality DAO that can be used as hydrocracker feedstock, they also yield a high-sulphur asphaltenic residue that can be difficult to utilise economically.

Some of this residue can be economically converted to higher-value products such as bitumen, but it is also typically used as an on-site fuel. This, however, can increase a refinery's sulphur dioxide (SO2) emissions.

However, Stéphane Charest, Business Development Manager, Cansolv Technologies Inc., describes an elegant solution for a scenario in which crude vacuum distillation products are sent directly to the hydrocracker (VGO) and to a ROSE unit (vacuum residue).

"The DAO produced by the ROSE unit would be sent to the hydrocracker for further upgrading, while some of the asphaltenic residue product from the ROSE unit could be blended in the fuel oil and fuel the boiler that generates steam and power for the refinery. A Cansolv SO2 Scrubbing System treats the boiler stack emissions; thus, the use of the residue as boiler fuel would be unlocked. It is a complete bottoms-management solution."

Cansolv Technologies Inc. is wholly owned by Shell Global Solutions International BV.

Key truth: Applying a regenerable flue gas SO2 absorption process to residue-fired utility boilers provides an effective alternative for refiners when residue volumes are not substantial enough to justify capital-intensive bottoms conversion units.

6. Be prepared to be adaptable

Hydrocracker projects are long-term initiatives that could potentially be derailed by external events. But, says Robert Riedelmeier, Hydroprocessing Advisor, Shell Global Solutions (US) Inc., operators should challenge the licensor to find a new solution that is within their constraints.

"For instance, if it seems that the costs are skyrocketing owing to external factors, you might be able to change the process configuration, phase the implementation or rescale the units. None of that is easy, and it may mean having to adapt previously designed equipment, but it could rescue the project.

"As an example, when a customer called to inform me that a project had been cancelled, we worked with the company and found a way to reduce the amount of hardware and the quantity of catalyst that were required – and the capital expenditure – and thereby saved the project," he says.

Key truth: Adaptability is a key attribute of a successful project. When external factors change, the design can usually be adjusted, but it requires both flexibility and top-tier operational expertise.