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Improving Margins by Increasing Diesel Yields For Petrotel-LUKOIL
A customised solution has enabled Petrotel-LUKOIL to increase the light cycle oil in its diesel hydrotreater (DHDT) feed blend while simultaneously restricting product sulphur and polynuclear aromatics without compromising on cycle length.
A combination of location and regional market conditions made it very important for Petrotel-LUKOIL to increase the performance and competitiveness of the DHDT at its Ploieşti refinery, 300 km inland from Romania’s Black Sea coast.
As the smallest but best-equipped of the Moscow-based LUKOIL group’s eight refineries, the 47,800-bbl/d Ploieşti plant needed to outperform what Technical Manager Niculescu Catalin describes as a “supersaturated” regional market. Another priority was to meet stringent EU biofuel requirements without incurring high capital costs.
“In 2010, the need to improve conversion rates and product refinement became a significant issue for us. At the same time, we had to meet growing demands for Euro V diesel and accommodate a continuously growing bio-component,” Catalin explains.
When asked to help, Criterion focused on quickly developing, testing, proving and validating plans to revamp the existing DHDT in co-operation with Petrotel-LUKOIL’s own expert team.
After 18 months of close collaboration, the team arrived at a solution that should improve the refinery’s bottom line by almost $5 million every year and has avoided the tens of millions of dollars otherwise necessary to construct a new unit, as based on current approximations of refinery economics.
Criterion’s ability to demonstrate that its proposed solution would work and deliver in practice was crucial to LUKOIL’s decision-making units in Romania and Moscow. The company gave the green light for go-ahead very swiftly.
The refinery’s inland location, far from the nearest oil terminal, creates a logistical handicap in terms of oil supply and product shipment. Overall, this reduces economic efficiency.
Everyone worked together with an open mutual exchange of data and ideas that led to a clear bilateral understanding of conditions and objectives.
One way to increase the DHDT’s margin is to process more light cycle oil. Light cycle oil is a low-value intermediate typically used for fuel oil blending because of its high aromatic content and, because it is relatively dirty, it is usually sent to the fuel oil pool. However, blending it into the diesel pool is generally more profitable.
While increasing the light cycle oil feed blend from 7 to 11 wt%, Petrotel-LUKOIL also wanted to maintain a two-year cycle length, product sulphur at 9 ppmw and product polynuclear aromatics at below 8 wt%. At the same time, it needed to reduce the product density from 843 to 840 kg/m3. This was, in part, a consequence of increasing the light cycle oil proportion but also because the refinery needed to blend 5 wt% biofuel into its products to meet EU requirements.
To meet these many requirements, Petrotel-LUKOIL initially asked several potential vendors, including Criterion, to consider its specifications and propose technical options.
Criterion’s initial response was to offer a range of possible options, which it discussed in detail with Petrotel-LUKOIL’s specialists. The option selected, Shell internals and catalysts from Criterion, fits in with the broader economic circumstances at the Ploieşti refinery. It involves low capital cost in the short term but delivers early performance benefits. However, it was what followed the initial talks that convinced the Romanian team to go ahead with Criterion. The catalyst company made clear that it would propose a solution on paper and was willing to undertake trials on the feed in question and discuss the results.
“Criterion’s offer of pilot plant testing meant that a customised catalyst system could be created. This was one more important warranty that its solution was viable,” says Rogojanu Marcello, Petrotel- LUKOIL’s process engineer responsible for hydrotreating processes. “The results of the laboratory testing indicated that our quality objectives would be met and surpassed. We had no similar assurances from other vendors. This was one more sound technical reason for going with Criterion.”
This was an intentional policy, as Steve Wake, Regional Manager, Criterion Catalysts & Technologies, explains. “We wanted to show that what we proposed was much more than a theoretical concept. This is why we asked for feedstock samples that were very similar to those to be processed. Six weeks of pilot plant testing in Amsterdam, the Netherlands, validated the proposals that we were putting forward. This was unusual for our Petrotel-LUKOIL counterparts but it gave them confidence that what we were promising was deliverable.”
Criterion also carried out additional modelling and discussed technical options with the Shell Global Solutions licensing team. When the refinery management had selected a solution, Wake then presented this, along with test evidence, to LUKOIL’s vice president of refining in Moscow, who gave his full support.
“It is important to understand why enhancing the reactor internals enables more light cycle oil to be processed,” Wake adds. ”Installing Shell internals substantially increases the volume of catalyst available. For instance, the new internals raised the overall catalyst utilisation by some 44% in one of the unit’s reactors. This enables the refinery to process the levels of light cycle oil it envisaged.
“The other issue is maintaining the cycle length at two years. If they had kept things as they were, they could have processed more light cycle oil but the cycle length would have been shorter. So, the combination of Shell reactor internals and our best catalysts enables Petrotel-LUKOIL to maintain a two-year cycle, process more light cycle oil and still make more money. I think that can only be described as a genuine win–win answer.”
Results count. “Although we have only had a short period in which to draw conclusions, our preliminary assessments show that the promised performance objectives are being achieved, as forecast in the feasibility study,” says Marcello.
Though the technical solution was impressive, being prepared to go the extra distance to confirm in practice what was actually achievable was of fundamental importance to winning the contract. “The co-operation achieved between our respective top professionals made this project a success,” says Catalin. “Everyone worked together with an open mutual exchange of data and ideas that led to a clear bilateral understanding of conditions and objectives. It is an excellent result.”