Catalysis 2024 Issue

Catalyst rejuvenation offers circular solution for hydroprocessing catalysts

Recover the full activity of spent hydrotreating catalyst to ensure their reuse without performance loss

Jignesh Fifadara and Madeline Green Evonik

T oday’s refiners face the daunting task of transform - ing an ever-changing crude slate into a wide range of marketable products. With a continuous emphasis on profitability under increasingly stringent environmental reg - ulations, the most advantageous path is not always clear. Surging energy costs and pressure to reduce environ - mental footprints have thrust the industry into the limelight, compelling a comprehensive overhaul and revitalisation of its operations to reduce waste, cut pollution, and minimise impact on the environment. Alongside the transition to greener, more sustainable man - ufacturing processes, refiners are contending with seemingly relentless cost increases. These external factors have placed further pressure on businesses to find economically efficient and sustainable methods to complete their operations with - out compromising performance or safety levels. Here lies the million-dollar question – how do you reduce operating costs and carbon emissions without sacrificing performance? One proposed solution is catalyst regeneration and reju - venation, which can combine performance and cost savings while potentially supporting circularity and sustainability goals by minimising environmental impact and reducing waste. Circular approach Historically, a linear model has been the norm, whereby raw materials are collected, turned into products – hydrotreat - ing catalysts, for example – and then disposed of as waste. However, this approach has its downsides. First, there is the

economic cost to the refinery – disposal of a catalyst can be expensive – followed by the additional cost of procuring a fresh catalyst to replace it. Then there is the environmental impact: more landfill waste and further depletion of resources to create new catalysts. A more ‘circular’ approach offers a clear path towards better profitability, competitiveness, and a reduced environmental footprint. Sustainable catalyst processes such as catalyst reju - venation, which focuses on reusing a catalyst after its lifecycle, pose a viable solution for those looking to steer operations away from wasteful practices. Benefits include minimised waste, lower greenhouse gas (GHG) emissions, and optimised raw material usage, as well as improved supply security, lower costs, better margins, and a boost to economic growth. Regenerate and rejuvenate So that is the ‘why’; now let us look at the ‘how’. Take Evonik’s proprietary Excel rejuvenation technology, which recovers the full activity of spent hydrotreating catalysts, including the highly active Type II, ensuring their reuse in refining hydro - treating applications without the loss of unit performance. The process consists of multiple steps to maximise activity recovery and restore performance. These include: • Catalyst analysis/qualification , whereby each batch undergoes thorough scrutiny and analysis. • Regeneration , which requires the optimal temperature to recover activity without causing damage to the catalyst. • Rejuvenation , a chemical treatment process to recover the original surface area, redisperse metals, and restore active sites for maximum activity. The technology is relevant to downstream oil refining, par - ticularly in hydrotreating applications including, but not lim - ited to, naphtha, kerosene, gasoline, ultra low-sulphur diesel (ULSD), gasoil, and hydrocracker pretreaters. When it comes to hydrotreating, catalysts are currently replaced in reactors after an interval of six months to four years or more, depending on feed severity and application type. During a cycle, the catalyst experiences coke and sul - phur accumulation, obstructing active sites and serving as the main cause of the catalyst’s deactivation. Active metals also agglomerate, reducing the availability of active sites and thus impeding catalyst activity. These two deactivation methods are reversible through regeneration










FCC gasoline





Figure 1 Excel rejuvenation is applicable to hydrotreaters throughout the refinery, as displayed by the green highlighted units


Catalysis 2024

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