Some recommendations on refinery catalyst testing

Ideally, the refinery should start the catalyst selection process 18-24 months before the next catalyst change-out to provide sufficient time for all tasks involved. Typically, catalyst lead time is 6-12 months leaving the rest for planning, evaluation, and internal processing. To put it simply - the earlier, the better.

As a general practice, the refiner should apply a multi-disciplinary approach to agree on catalyst requirements, e.g., longer run length or more difficult feedstocks. On top of that, the focal point (usually a unit process engineer) shall also incorporate current operating issues, e.g., high reactor pressure drop, into the ITB so the catalyst supplier can properly address the problems in the next cycle.

While some refiners still rely on vendor estimations/predictions, pilot plant testing has become more popular over the years as a tool to unveil the actual catalyst performance. This evaluation approach is particularly crucial to a critical unit like hydrocracker, where a slight difference in product yield can result in multi-million dollars profit/loss per year.

In contrast with a general notion, comparing paper estimates/predictions from different catalyst vendors is not an apple to apple comparison but is nonetheless prevalent among refiners due to its simplicity. As a matter of fact, catalyst vendors employ different design assumptions, feed characterization techniques, kinetic models, and product property estimators, e.g., basic to non-basic nitrogen ratio or aromatics distribution. ?Consequently, it is fundamentally wrong to compare estimates/predictions between catalyst vendors. Sadly, quite many refiners are unaware of this fact.

Despite the mentioned shortfalls, it is still acceptable to use paper-based evaluation for a less critical application, e.g., naphtha hydrotreater. Although, the best practice is to have your catalysts tested before the actual reloading.

For refiners who do not have an in-house pilot plant testing facility, several companies out there can also provide an independent pilot plant testing service. At the moment, there are two available primary methods

1. Full pilot scale, e.g., C-solutions
2. High throughput bench scale, e.g., hte GmbH or Avantium

Each method has its own advantages/disadvantages. It is at the refiner's discretion to select the best independent pilot plant testing laboratory to suit their requirements and constraints. To my own experience, both approaches provided adequate essential information for hydrocracking catalyst selection. It must be noted that some laboratories are more favored by refiners than others. As such, the refiners should proactively contact these independent laboratories as soon as the new cycle starts. I have heard a story about a laboratory that requires at least 24 months of pre-booking before the actual test date.

From my recent experience, the testing fee for each catalyst loading scheme can range between 45,000-95,000 dollars. A more important question is who will pay for the test. The refiner may pay for the total cost or ask the catalyst suppliers to share. In general, the willingness of the catalyst supplier to share the cost increases with the value of the catalyst package.

Although the independent pilot plant catalyst testing seems costly on the surface, it is worth every penny to my own experience. I personally recommend everyone to go for it.