Depending on the concentration ranges, sample matri- ces, and dilution levels used, these errors themselves can also become the primary source of error. Significant sources of difference in multiple repeats are the error in the temperature of the reactor heater, which ranges within ±1.0°C (1.8°F) and the error in the distribution system rep- resented by the mass balance, which is generally equal to ±2%. Other typically negligible errors that affect the mass balance include the loss of lighter hydrocarbons from the liquid samples and the reproducibility of gas phase chro- matogram integrations. The online gas chromatography (GC) peak integration is fine-tuned for each project. When the amount of gas phase produced is above 10/15%, however, many peaks start over- lapping, which then requires a different automatic GC peak integration routine. In the present study, the mass balance differences were minimised by adjusting the capillary tem - peratures, which made this error negligible compared to the heater’s related error. If the catalyst batch used is not homo- geneous, such an error can also affect data repeatability. While this type of error is unlikely when commercial cata - lysts are used, it can be more relevant when testing research samples. Some differences in activity with commercial catalysts may be observed if different batches are tested. Finally, when reactors in series are used, as in this case, Zeopore researchers have dedicated significant effort to stepping away from the state-of-the-art linear mesop - orisation path (see Table 1 ), exploring the various routes present in the faujasite landscape to arrive at a mesoporous high-SAR USY. In doing so, the classical dealumination fol - lowed by the mesoporisation route is abandoned, opening up a wide variety of synthetic options within the two- dimensional faujasite landscape. In this landscape, the researchers have managed to avoid the many pitfalls, overcome stubborn challenges, and exploit unexpected synergies. They have established a route that not only attains the required high-quality USY zeolite but does so using exclusively scalable and low-cost ingredients, including the parent zeolite. The limitation of slower solubilisation of CO 2 due to its poor solubility in water can be overcome using a suitable unit to increase mass transfer area between gas and liq- uid phases, allowing maximum CO₂ use in the process. It is also possible to use gaseous effluent from thermal energy plants or refineries, having CO₂, nitrogen (N₂), nitrogen oxide (NOx) and sulphur dioxide (SOx), depending on fuel type. However, if SOx and NOx are present, they will react faster than CO₂ and further reduce the pH. The risk of H2S evolution remains in such a case if pH drops to an acidic 30 Multiplication of the relative strong acidity with the mes - opore volume yields a much-improved relationship with the middle distillate yield (see Figure 5, left ). Similarly, the activity number relates better to the activity of the cata - lysts (see Figure 5, right ). These descriptors highlight the need to prioritise both mesopore quantity and quality in the synthesis of superior high-quality USY zeolites for hydrocracking. Integrated dealumination and mesoporisation 20 With petroleum coke, there was no removal of COD com- ponents from the spent caustic. Instead, the spent caustic desorbed other organic compounds, increasing the COD values. It is not surprising due to the ionic nature of organic compounds under strongly alkaline conditions. The result- ing contribution to the COD does not allow their adsorption on coke. When pH is reduced and phenolic compounds are converted into a molecular form in the present studies, their adsorption on activated carbon improves significantly. Conclusion 10 0 TOS (day) A ILs tend to have high viscosities at ambient tempera- tures, which can limit mass transfer rates, although the high removal efficiencies result from a large mass transfer driving force. The adsorption of organics from spent caustic solutions on bleaching earth, alumina, and petroleum coke has been reported under alkaline conditions.3 B 60 Bleaching earth could reduce COD values by 60%, prob- ably by ion exchange and/or intercalation of the organic ani- ons between layered structures. However, alumina-based adsorbent reacted chemically with alkali, resulting in adsor- bent bed collapse in the column. 0 20 for the doubled middle distillate yield compared to the other mesoporous sample, as well as the surprisingly increased activity compared to the conventional USY zeolite. 40 20 30 80 Table 1 100 Mesoporosity 120 SiO₂/AI₂O₃ ratio 140 160 16.0: PT3 1.0: PT1 7.0: PT2 8.0: PT2 9.0: PT1 11.0: PT1 15.0: PT3 3.0: PT1 10 0 0 40 50 80 60 90 70 100 Aspect Optimal mesoporous NaY Cost Medium Low Low High High Very low Having a high-quality USY zeolite does not necessarily imply commercial relevance (Figure 3). For example, even if a high-quality mesoporous zeolite can be achieved without the need for costly organics, the dependency on a costly high-silica-alumina-ratio (SAR) starting USY complicates the business case. The treatment of highly alkaline waste streams using CO 2 provides a sustainable solution. The phenolic compounds are removed by bringing the pH of the solution below pKas of phenol(s) and efficiently separating the oil phase. (In molecular form, phenol and cresylic acids have poor solu- bility in water). The phase separation needs to be improved by a solvent extraction step, using an organic solvent that can dissolve the separated phenolic oil. However, neutralisation by CO 2 is restricted to free alkali and alkali salts of phenols. Thiophenols and all naphthenic acid(s) remain in the solu- tion because of their stronger acidic nature.
the errors affecting the concentration of nitrogen (c(N)) also propagate to the results obtained with the hydrocracking reactors. The cracking catalysts will experience slightly dif- ferent nitrogen concentrations, potentially leading to small variations in hydrocracking performance. Therefore, when analysing any benchmarking test results, it is important to consider these limitations to ensure that the observed differences are significant, especially in the absence of system repeats. hte typically reports a repro- ducibility of ±1.5°C among reactors. This temperature variability can be observed when it is necessary to reach a target parameter between multiple repeats running in parallel in one unit or when comparing the same catalysts converting the same feed in different hte units. As previously mentioned, the performance of a hydrocrack- ing catalyst is affected by the pretreatment activity. The N in the pretreated liquid product can passivate and temporarily deactivate the active sites of the cracking catalysts. This phe- nomenon can also be observed in Figure 3 , where it is possi- ble to see that, when the N concentration increases (panel A), the conversion of the fraction heavier than 375°C decreases (panel B) from a TOS of one to six days. These changes in the activity of the hydrocracking catalyst, due to varying N concentrations, were observed because the hydrocracking reactor temperatures were not adjusted. 5 K. De Jong et al., Zeolite Y crystals with trimodal porosity as ideal hydro - cracking catalysts, Angewandte Chemie , 2010, 49, 10,074-10,078. 6 L. Vaugon et al. , Impact of pore architecture on the hydroconversion of long chain alkanes over micro and mesoporous catalysts, Petroleum Chemistry , 2020, 60, 479-489. 4 Roudsari, M. H., Soltani, M., Seyedin, S. H., Chen, P., (2017) Investigation on New Method of Spent Caustic Treatment, J. Multidisc. Eng. Sci. Technol. , 4(6), 7459-7464. 5 Kumfer, B.J., Felch, C.L., Brandenburg, B., Ishmann, R.R., (2014), US patent, 8,734,648 B2, Siemens Energy, Inc., Orlando, FL (US). 6 Doble, M., Kruthiventi, A. K., Gaikar, V.G., (2004) Biotransformation’s and bioprocesses, Marcel Dekker, New York. 390 Outlook By understanding the complex material properties and exploiting synthetic potential, unique mesoporous USY zeolites and related means of manufacture have been cre - ated. This advancement creates a valuable position to bring the promising catalytic benefits of accessible USY zeolites to the refiner. 385 References 1 Pino-Cortés, E., Montalvo, S., Huiliñir, C., Cubillos, F., Gacitúa, J., (2020) Characteristics and Treatment of Wastewater from the Mercaptan Oxidation Process: A Comprehensive Review, Processes , 8, 425; doi:10.3390/pr8040425. References 1 D. Verboekend et al ., Synthesis, characterisation, and catalytic evalua - tion of hierarchical faujasite zeolites: milestones, challenges, and future directions, Chemical Society Reviews, 2016, 45, 3,331-3,352. 2 K. Du Mong, D. Verboekend, Low-cost mesoporous zeolites deliver catalytic benefits, PTQ Catalysis , 2022, 45-49. 3 S. Torrisi, J. Den Breejen, Boosting hydrocracker heavy feed conver - sion, PTQ Catalysis , 2020, 1-7. 4 D. Verboekend, Enhancing C8+ aromatics conversion, Hydrocarbon Engineering , November 2024. 2 Rita, A.I., Rodrigues, C.S.D. Santos, M. Sanches, S. Madeira, L.M., (2020) Comparison of different strategies to treat challenging refin - ery spent caustic effluents, Sepn. Purifn. Technol., 253, 117482-97, https://doi.org/10.1016/j.seppur.2020.117482. 380 375 T_Rx (˚C) 0 20 40 We believe that using a CO 2 waste stream to treat another waste solution is a sustainable solution. Such positive solu - tions can have a positive and profitable effect across the entire spectrum of the oil industry. 60 80 100 In refineries, the spent caustic stream is mixed with other aqueous solutions, diluting the spent caustic effluent. If the spent caustic from the kerosene treatment unit, with its remarkably high load of phenolics, is treated directly with CO 2 , the process may provide an economic incentive to recover phenols as a valuable product. 140 120 160 16: PT3 1: PT1 7: PT2 8: PT2 9: PT1 11: PT1 15: PT3 3: PT1 Conventional USY State-of-the-art mesoporous Medium Very high High Low High High level, demanding a secondary treatment unit for the cap- ture of H 2S. C 30 20 14.0: PT1+HC2 4.0: PT1+HC1 5.0: PT1+HC1 2.0: PT1+HC1 12.0: PT1+HC2 10.0: PT1+HC2 6.0: PT1+HC1 13.0: PT1+HC2 7 T. C. Keller et. al., Design of hierarchical zeolite catalysts for the manufacture of polyurethane intermediates, ACS Catalysis , 2015, 5, 734-743. 8 V. Rac et al. , Hierarchical ZSM-5, Beta and USY zeolites: Acidity assessment by gas and aqueous phase calorimetry and catalytic activ - ity in fructose dehydration reaction, Microporous and Mesoporous Materials, 2014, 194, 126-134. Danny Verboekend is a founder and CSO of Zeopore Technologies. He is engaged in the strategic development of novel materials using strictly low-cost and scalable manufacturing routes, for established and novel (circular) catalytic applications. K V Seshadri is Adjunct Professor in the Department of Chemical Engineering at the Institute of Chemical Technology, Matunga, Mumbai-400019, India. Vaibhav B Kamble is a post-graduate student in the Department of Chemical Engineering at the Institute of Chemical Technology, Matunga, Mumbai-400019, India. 7 Sabri, M.A., Ibrahim, T.H., Khamis, M.I., Nancarrow, P., Hassan, M.F., (2018) Spent caustic treatment using hydrophobic room temperatures ionic liquids, J. Ind. Eng. Chem ., 65, 325–333, https://doi.org/10.1016/j. jiec.2018.05.002. Dr Vilas G Gaikar is Bharat Petroleum Chair Professor. Email: vg.gaikar@ictmumbai.edu.in 3 Czimer, B., Kovács, A., Petró, J., (2015) Treatment of Spent Merox Caustic Waste in Industrial Ecology Frames, Period. Polytech. Chem. Eng. , 59(3), 215-220, DOI: 10.3311/PPch.7601).
Distinct routes for preparing mesoporous USY zeolites for hydrocracking
TOS (day)
Figure 3 A: c(N) vs time on stream, B: X ( >375) vs time on stream, C: activity plot: c(N) vs reactor temperature (T_Rx)
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