Catalytic Conversion of n-C7 Asphaltenes and Resins II into Hydrogen Using CeO2-Based Nanocatalysts

Abstract

This study focuses on evaluating the volumetric hydrogen content in the gaseous mixture released from the steam catalytic gasification of n-C7 asphaltenes and resins II at low temperatures (<230 °C). For this purpose, four nanocatalysts were selected: CeO2, CeO2 functionalized with Ni-Pd, Fe-Pd, and Co-Pd. The catalytic capacity was measured by non-isothermal (from 100 to 600 °C) and isothermal (220 °C) thermogravimetric analyses. The samples show the main decomposition peak between 200 and 230 °C for bi-elemental nanocatalysts and 300 °C for the CeO2 support, leading to reductions up to 50% in comparison with the samples in the absence of nanoparticles. At 220 °C, the conversion of both fractions increases in the order CeO2 < Fe-Pd < Co-Pd < Ni-Pd. Hydrogen release was quantified for the isothermal tests. The hydrogen production agrees with each material’s catalytic activity for decomposing both fractions at the evaluated conditions. CeNi1Pd1 showed the highest performance among the other three samples and led to the highest hydrogen production in the effluent gas with values of ~44 vol%. When the samples were heated at higher temperatures (i.e., 230 °C), H2 production increased up to 55 vol% during catalyzed n-C7 asphaltene and resin conversion, indicating an increase of up to 70% in comparison with the non-catalyzed systems at the same temperature conditions.

Catalytic Decomposition of n-C7 Asphaltenes Using Tungsten Oxides–Functionalized SiO2 Nanoparticles in Steam/Air Atmospheres

“…The precipitated asphaltenes were filtered and washed with n-heptane until obtaining a shiny black tone. Details of the chemical and physical properties of the asphaltenes can be found in previous work [29].…”

“…However, at lower temperatures (<200 • C), the higher release of them was noted because of the breaking and decomposition of aliphatic chains and low-molecular-weight hydrocarbons. Finally, H 2 release was poor in the noncatalyzed sample because these heavy fractions follow other reaction mechanisms that prioritize the production of other gases, such as CO 2 and CO [29].…”

“…During this process, different reactions occur simultaneously, generating physicochemical changes in the heavy oil, even leading to upgrading through viscosity reduction and API gravity increase. Nevertheless, the conversion of heavy and refractory fractions such as asphaltenes into lighter compounds struggles to occur behind the combustion zone, as the decomposition temperature could be higher than 400 • C [28][29][30][31].…”

Field Applications of Nanotechnology in the Oil and Gas Industry: Recent Advances and Perspectives

“…Regarding TEOR, there are many opportunities for nanotechnology implementation to improve related processes. For example, in situ upgrading technologies , based on heterogeneous catalysis are promising in the way that the quality of crude oils can be greatly enhanced, in terms of increase of API gravity, viscosity reduction, reduction of carbon residue, as well as coproduction of valuable sub products such as hydrogen, and light hydrocarbons with reduction of CO 2 emissions . Also, a positive side effect could be the optimization of the operational requirements of the process of steam injection by reducing the water consumption, as well as the energy needed during steam generation, which has a direct impact on the emissions footprint.…”

Electrochemical Reduction of CO2: A Review of Cobalt Based Catalysts for Carbon Dioxide Conversion to Fuels

“…Catalysis plays a vital role in our daily life. Various types of catalysts have been reported for the conversion of waste into useful products, including zeolites [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], metal and metal oxides [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], nitrides [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ], carbon-based catalysts [ 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ], metal complexes [ 64 , …”