Investigating active phase loss from supported ruthenium catalysts during supercritical water gasification

Abstract

Ru loss mechanisms were investigated for the first time in SCWG by ICP-MS. Ru leaching at steady state was very low, close to thermodynamic models. Abrupt changes in process conditions must be avoided to prevent catalyst damage and higher Ru loss.

On the selective desulphurization of biomass derivatives in supercritical water

“…1), from 1300 to 1800 m 2 ⋅g − 1 , the pore volume following the same proportional increase (30% increase). This increase is indicative of a transformation of the pore structure, and has been observed already on activated carbons under SCW [37]. This is supposedly originating from the partial gasification of the carbon (non-stable part) but could also originate from the migration of metals from inside the pores to the outer surface.…”

Advanced Analytical Study of Process Streams for a Rational Optimization of Hydrothermal Gasification

“…The analysis of Ru flowing in and out of the reactor indicated a flow of 0.8 ± 0.4 mg Ru ·h –1 exiting the reactor (1.1 ± 0.4 mg Ru ·L –1 in the process water, see the Supporting Information) over an average of 4 h. This value remained in the same range in the sample collected from time on stream 9–24 h. This is to be compared to the 24 g of ruthenium present in the reactor. However, this is not negligible for long operation time and triggered further investigations . The flow of Al and Zn, which are major constituents of the (sulfur-) trap, barely varied from the inlet to the outlet of the catalytic reactor.…”

“…However, this is not negligible for long operation time and triggered further investigations. 19 The flow of Al and Zn, which are major constituents of the (sulfur-) trap, barely varied from Figure 3. Sankey diagram of the ash, carbon, and total mass flows, throughout the catalytic hydrothermal gasification testing unit using pine wood HTL process water concentrated by recycling.…”

“…The best-performing catalyst for hydrothermal gasification known to date is ruthenium supported on activated carbon (Ru/AC). Ru offers high gasification rates and excellent selectivity to methane, allowing to reach thermodynamic equilibrium and good stability toward sintering ,, and leaching, while AC is one of the rare catalyst supports that is stable in supercritical water (SCW) and offers both high surface area and low cost . If a proper space velocity is used, all liquefied organic matter dissolved in supercritical water will be gasified to a thermodynamically equilibrated synthetic natural gas by such a catalyst.…”

Surface Decomposition of Doped PrBaMn2O5+δ Induced by In Situ Nanoparticle Exsolution: Quantitative Characterization and Catalytic Effect in Methane Dry Reforming Reaction

“…Supported metal catalysts are extensively used in various chemical and energy-conversion processes. − The solid support not only offers a high surface area to enable the robust mono-dispersion of metallic nanoparticles (NPs), but importantly, also creates the metal-support interaction, manipulating the selectivity and activity of the catalysts. In the industrial operation, all catalysts inevitably suffer from activity degradation due to various mechanisms such as poisoning, fouling, coking, and NP sintering. − Unfortunately, the regeneration of the spent catalysts remains a grand challenge: some of the degradations are fully irreversible; many regeneration processes also lead to the structural degradation of the catalyst. In the real-life practice, it is common that such spent catalysts are subjected to the “recycling” process to retrieve the precious metals and minerals.…”