ERTC 2025
Closing the loop on catalyst waste: a circular vision for refining
Markus Hartung Evonik Catalysts
In North America, rejuvenated CoMo catalysts in a distillate hydrotreater showed excellent stability and low deac- tivation rates. In both cases, refiners achieved significant cost savings of up to 70% alongside meaningful Scope 3 emis- sion reductions, proving that performance does not need to be compromised in pur- suit of sustainable solutions. Since 2015, Evonik has treated more than 16,000 tons of catalysts through Excel Rejuvenation and more than 250,000 tons through regeneration. Each load represents avoided waste, reduced emissions, and extended value for refiners navigating the energy transition. Catalyst circularity enables refin- ers to align with decarbonisation goals while strengthening operational reliabil- ity. Instead of discarding hundreds of thou- sands of tons each year, they can close the loop: reuse, restore, and reapply catalysts. Length grading complements this loop by ensuring that only robust material remains in service, raising overall process efficiency. rejuvenation, and length grading are shifting refiners towards a more environmentally conscious future in hydroprocessing, while simul- taneously reducing operating costs and maximising profitability at a critical junc- ture for the industry. These are not just technical steps, but enablers of refinery sustainability. Looking ahead Catalyst regeneration, Evonik’s technology proves that perfor- mance does not need to be sacrificed in efforts to lower emissions. Catalyst rejuve- nation can support businesses in minimis- ing waste and reducing carbon footprint, all while maintaining stable and equivalent performance to fresh catalysts. It has been identified by externally certified Life Cycle Assessments that the use of these rejuve- nated catalysts results in a 60% reduction in CO₂eq/per kg of catalyst global warm- ing potential (GWP) emissions compared to fresh catalysts. Cost savings of 30-50% are provided by Excel rejuvenation technology when pur- chased directly from Evonik’s inventory, and up to 50-70% savings when refining organisations reuse catalysts within their own systems. Evonik provides a compre- hensive solution for companies seeking to optimise performance while adopting a greener, more circular approach to cata- lyst management. By reducing waste, cutting emissions, and extending catalyst lifetimes without compromising performance, circularity is no longer a distant vision; it is a practical reality for refiners today.
The chemical industry supports nearly 96% of all manufactured goods. Yet, its environmental footprint and contribution to emissions cannot be disputed, with refineries discarding enough hydropro- cessing catalysts each year to fill a football stadium. However, the global landscape is being reshaped by lower fuel demand growth, weak profit margins, and increas- ingly stringent CO₂ regulations, as well as legislative pushes for renewable fuels. Consequently, refiners face the complex challenge of navigating how to maintain competitiveness while reducing environ- mental impact and controlling operational costs. Evonik’s solution to this combines regen- eration, Excel ® Rejuvenation, and an addi- tional process known as length grading. The result: spent catalysts perform at near-fresh levels, while cutting Scope 3 CO₂ emissions by as much as 60%. A Call for Circular Solutions Hydroprocessing catalysts are essen- tial to refinery operations, but their deg- radation forces frequent replacement. In a diesel hydrotreatment reactor (ultra- low sulphur diesel [ULSD] application), catalysts are typically replaced after an interval of four years. The replacement of spent catalysts results in significant expenditure and waste, with more than 350,000 tons of spent catalyst sent to landfills annually. Only 15-20% of these catalysts are typically regenerated, leaving behind haz- ardous residues that pose environmental risks and contribute to Scope 3 emissions. For European refiners under increasing pressure to meet strict sustainability tar- gets, this is no longer viable, driving urgent demand for circular solutions. Evonik’s regeneration, Excel Rejuvenation, and length grading technologies emerge as a powerful approach that marries per- formance with cost savings. By regenerat- ing and rejuvenating spent catalysts, their activity and selectivity are restored to near- original levels. This circular technology con- tributes to minimising environmental impact and reducing waste across the chemical industry. Evonik’s Integrated Rejuvenation Process Excel Rejuvenation technology offers a more sustainable pathway for extend- ing the lifecycle of hydroprocessing cata- lysts. Designed to recover the full activity of spent hydrotreating catalysts, includ- ing the highly active Type II, this process secures their reuse in refining hydrotreat- ing applications without compromising unit performance. This process comprises verification, regeneration, rejuvenation, and length grading.
CO emissions involved in HPC Catalyst Production Comparison of Fresh vs Excel
Circular economy & Excel Rejuvenation
14000
Raw material
Waste
Excel
Fresh
11992
12000
Hydrotreating catalyst manufacturing
Recycling
10000
8000
7348
5884
Fines/shorts
6000
4992
4446
4000
Hydrotreating unit
Regeneration & Excel rejuvenation
2000
722
Transport 170 198
0
End of cycle
Raw material processing
Finished product manufacturing
Total
Left, CO₂ emissions in HPC catalyst production; Right, the circular economy and Excel rejuvenation
did you know? Catalyst circularity slashes CO₂ by 60% – a gamechanger for sustainable refining naphtha, kerosene, gasoline, ULSD, gas- oil, and hydrocracker pretreaters. Since its commercial rollout in 2015, the technol- ogy has been deployed in refineries world- wide, consistently meeting or exceeding performance expectations. Together with length grading, Evonik’s regeneration and rejuvenation technolo- gies provide a circular solution by maxim- ising the value of existing catalyst material and minimising waste. Through the val- orisation of raw materials, catalysts are utilised to their full potential, signifi- cantly lowering the environmental foot- print of refinery operations. Collectively, these techniques contribute to reducing Scope 3 emissions and promoting sustain- able refining practices. Proven Performance: Case Study Case studies indicate that restoring spent catalysts to near-fresh performance levels makes them viable for demand- ing applications such as ULSD produc- tion. In European ULSD service, Excel Rejuvenated NiMo catalysts performed on par with fresh catalysts across hydrodes- ulphurisation, hydrodenitrogenation, and aromatic saturation.
○ Verification ensures that only cata- lysts of the highest quality are eligible for reuse. As well as being free from contami- nants, catalysts are required to meet strict chemical and physical specifications to go through the rejuvenation journey. ○ Regeneration involves an oxidation reaction to remove carbon and sulphur. Evonik’s moving belt technology minimises attrition, maximises yields, and maintains physical properties, restoring 65-85% of original activity, depending on the original catalyst type. ○ Excel Rejuvenation then redistributes active metals on the catalyst surface, bringing performance close to fresh while reducing CO₂ emissions by about 60% compared with producing a new catalyst. ○ Length grading adds another dimen- sion by mechanically sorting and remov- ing damaged or undersized particles. This improves reliability, reduces pressure drop in reactors, and extends the useful cycle length. Evonik’s technology is applicable across both refining and re-refining operations and is compatible with all manufacturers of both CoMo and NiMo catalysts. Potential applications include, but are not limited to,
Contact: markus.hartung@evonik.com
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