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Hydrogen Production by Catalytic Reforming Process
Published in Sonil Nanda, Prakash K. Sarangi, Biohydrogen, 2022
Chandramani Rai, Prabu Vairakannu
Reverse water-gas shift and disproportionation reaction are suppressed towards the formation of CO, which deteriorates the catalyst activity (Abdullah et al., 2020). The selection of catalyst plays an important role in the dry reforming of methane One of the biggest challenges in the case of this process is the preparation of catalyst in such a way that it restricts the formation of coke. There are various types of catalysts such as noble metals (e.g., Rh, Ru, Pd, and Pt) and transition metals (e.g., Ni, Co, Fe, and Cu) (Zhang et al., 2017; Abdulrasheed et al., 2020) for dry reforming of methane This process is conducted using either a fixed bed or a fluidized bed reactor. As the operational cost of the fluidized bed is high, a fixed bed condition is preferred under the pilot-scale level. The quality of the gases produced during this process depends upon the types of reactors, catalysts, reactor temperature, pressure, and reactant ratio (CH4 and CO2). Furthermore, the catalyst preparation method plays an important role in the conversion and selectivity of the produced gas (Hambali et al., 2020). This reaction is also endothermic nature that requires the maintenance of high operating temperatures. The use of catalysts provides an alternate path to reduce the required temperature.
2 for Fuels and Chemicals
Published in Prasenjit Mondal, Ajay K. Dalai, Sustainable Utilization of Natural Resources, 2017
The worldwide shift from coal to natural gas is an approach that leads to lower CO2 emissions. However, methane, the major component of natural gas, is another powerful greenhouse gas. Thus, a small leakage of methane has a strong global warming potential (Howarth et al. 2011). In recent years, significant research has been dedicated to incorporate those two greenhouse gases in reactions that generate useful products. Dry reforming, for example, is a reaction in which methane reacts with CO2, producing syngas, a very important intermediate for various chemicals and fuels (CH4 + CO2 = 2CO + 2H2). In other words, dry reforming is another approach of chemical conversion of CO2 into higher-value chemicals.
Hydrogen Production
Published in Marcio Wagner da Silva, Crude Oil Refining, 2023
The methane dry reforming reaction is endothermic and conducted under high temperatures (higher than 700°C) over a nickel-based catalyst. The dry reforming production route is attractive from the environmental point of view because it can minimize water consumption, and the main reagent is a combustion subproduct that is partially responsible for the greenhouse effect. Another point in favor of dry reforming technology is that the syngas from this process has the ratio H2/CO = 1. This characteristic is ideal for producing oxygenated compounds such as acetic acid and dimethyl ether.
Life cycle assessment of biomass-based hydrogen production technologies: A review
Published in International Journal of Green Energy, 2023
Sakshi Singh, Gaurav Pandey, Gourav Kumar Rath, Hari Prakash Veluswamy, Nadezhda Molokitina
Some other technologies like dry reforming and tri reforming have also been studied by researchers. Less frequently used than steam reforming, dry reforming is primarily used for operations that call for a high concentration of CO in the syngas. Dry reforming has comparable thermodynamics to steam reforming. The primary functional distinction between steam and dry reforming is the coking property of dry reforming, which is exacerbated by the absence of steam for C- removal. Steam is supplied for successful coking issue management in some uses, such as mixed reforming (a combination of dry and steam reforming). Ru and Rh catalysts are usually employed in dry reforming activities because coking quickly turns Ni catalysts inactive (Camacho et al. 2022). The tri-reforming method efficiently creates synthesis gas (syngas) that is useful for industry by combining CO2 reforming, steam reforming, and partial methane oxidation of methane in a single reactor. Tri-reforming can provide synthesis gas (CO + H2) with suitable H2/CO ratios (1.5–2.0) and prevent carbon formation, which is typically a significant issue in the CO2 reformation of methane (Song and Pan 2004).
Advances in state-of-art valorization technologies for captured CO2 toward sustainable carbon cycle
Published in Critical Reviews in Environmental Science and Technology, 2018
Shu-Yuan Pan, Pen-Chi Chiang, Weibin Pan, Hyunook Kim
The most widely used catalysts for the CH4 dry reforming process are Ni-based; however, they typically undergo sever deactivation due to carbon deposition (Pakhare and Spivey, 2014). Thus, researches should focus on a thermally stable catalyst that can resist the deactivation caused by carbon deposition and sintering. The resistance of catalyst to deactivation can be promoted by choosing an appropriate basic support and a promoter as well as by using noble metals with high activity and of great carbon deposition resistance. Recently, noble metals have been studied to be incorporated with the Ni catalyst. In general, the activities of noble metals supported catalysts in the CH4 dry reforming are in the following order (Jones et al., 2008; Rezaei et al., 2006).
Tri-reforming of surrogate biogas over Ni/Mg/ceria–zirconia/alumina pellet catalysts
Published in Chemical Engineering Communications, 2018
Xianhui Zhao, Huong T. Ngo, Devin M. Walker, David Weber, Debtanu Maiti, Ummuhan Cimenler, Amanda D. Petrov, Babu Joseph, John N. Kuhn
For tri-reforming, pressure and material gaps exist between literature studies and anticipated industrial scale applications. First, catalysts in pellet form are used for methane reforming and partial oxidation to produce syngas at industrial scale reactors (Vita et al., 2015). Limited studies exist on tri-reforming on pellet scale catalysts. Using 1 mm Ni-Mg/β-SiC pellet catalyst for methane tri-reforming, García-Vargas et al. (2015) determined that low temperature favored both the steam reforming and the water gas shift reactions, while high temperature favored the dry reforming reaction. Izquierdo et al. (2013) compared the tri-reforming of biogas at both the microreactor (∼50 micron catalyst size) and a bench-scale fixed bed reactor (∼0.5 mm catalyst size) scales. The high CO2 and CH4 conversions obtained in the bench-scale fixed bed reactor were also reached in the microreactor operating at a much higher weight hourly space velocity. Neither of these studies addressed the role of pressure. Reforming reactors typically operate at high pressures (3–20 bar) to decrease reactor size (lower CAP-EX) and to meet the high pressure needs of FTS reaction (Farrauto and Armor, 2016). During dry reforming, lower energy consumption is one of the advantages of high pressure operations (Chein et al., 2015). During steam reforming, heat and mass transfer limitations are issues for the possibility of creating small-scale plants (Palma et al., 2016). Due to the complexity of three oxidants in the feed and the complex catalytic chemistry, additional engineering studies (such as heat and mass transfer limitations, gas expansion, pressure drop, etc.) are needed to push this technology into practice (Christiansen, 2016). This lack of studies is a key gap between research and practice (Farrauto and Armor, 2016).