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Water Dissociation Technologies for Hydrogen
Published in Yatish T. Shah, Water for Energy and Fuel Production, 2014
Previously, thermochemical cycles were characterized as those that use process heat at temperatures <950°C. These are expected to be available from high-temperature nuclear reactors. These cycles required three or more chemical reaction steps, and they are challenging because of material problems and inherent inefficiency involved with heat transfer and product separation in each step. One example is hybrid sulfuric acid cycle that requires two steps incorporating one electrolysis step. The leading candidates for multistep thermochemical cycles include mainly three-step sulfur—iodine (S—I) cycle based on thermal decomposition of sulfuric acid at 850°C and four-step UT-3 cycle based on hydrolysis of calcium and iron bromide at 750°C and 600°C, respectively [87–131] (Funk, 2011, pers. comm; Bamberger, 2011, pers. comm.).
Modular Systems in Natural Gas and Hydrogen Industries
Published in Yatish T. Shah, Modular Systems for Energy and Fuel Recovery and Conversion, 2019
Thermochemical cycles can be used to split water through a series of thermally driven chemical reactions where the net result is the production of hydrogen and oxygen at much lower temperatures than direct thermal decomposition. All supporting chemical substances are regenerated and recycled, and remain—ideally—completely in the system.
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Published in Eduardo Rincón-Mejía, Alejandro de las Heras, Sustainable Energy Technologies, 2017
Christian Sattler, Anis Houaijia, Martin Roeb
Thermochemical cycles use high heat sources to split water into its main components hydrogen and oxygen. There are several cycles, which take place in temperatures between 500°C and 2000°C. Figure 12.7 shows a classification of the different thermochemical cycles.
Thermodynamic analysis and optimization for steam methane reforming hydrogen production system using high temperature gas-cooled reactor pebble-bed module
Published in Journal of Nuclear Science and Technology, 2021
Yongle Zhang, Guang Hu, Huang Zhang, Qianfeng Liu, Junbo Zhou
Among all the hydrogen production methods, thermochemical cycle (I-S cycle [3–7], Cu-Cl [8–13], Mg-Cl [14–17] and Co-Cl [18]), Hybrid Sulfur Cycle (HyS cycle) [19–22], high-temperature steam electrolysis (HTSE) [23–27] and steam methane reforming (SMR) [28–31] have attractive prospects. However, the thermochemical cycle, such as the HyS cycle and HTSE, is either new technology or not particularly efficient at hydrogen production [17,22,30,31]. In addition, SMR has been extensively applied in various industries and accumulated much practical engineering experience [32–35]. Approximately 96% of the hydrogen produced today are extracted from the reforming of fossil fuel feedstocks, with SMR accounting for 49% [36]. And some studies [37,38] reported that the cost of hydrogen production via SMR reduces 255 $/ton H2 and decreases 8.8 kg CO2/GJ primary energy (natural gas fuel energy), when the heat is provided from the nuclear reactors instead of the combustion of the methane input. Thus, SMR using nuclear reactor as the heat source can produce hydrogen from the fully clean energy [39,40].
Uranium thermochemical cycle: hydrogen production demonstration
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Aimei Chen, Xiaobei Zheng, Chunxia Liu, Yuxia Liu, Lan Zhang
Based on the analysis of the product, it was concluded that the obtained solid product was α-sodium diuranate, and the reaction was finished in 3 h. There was hydrogen produced during this process as shown in the gas chromatogram of gas sample, which verified the hydrogen production step in the thermochemical cycle based on uranium. The quantitative analysis of H2 in the gas product was performed by the internal standard method, and the chemical conversion obtained by this method was relatively low, which might be attributed to the poor airtightness of the sodium hydroxide absorption bottle. This thermochemical cycle, as a process of producing hydrogen, has a high demand for the hydrogen yield, while hydrogen is more difficult to be sealed than other gases because of its minimum molecular weight, so improving the airtightness of the equipment will be the next challenge need to be conquered.
Computational intelligence approach for modeling hydrogen production: a review
Published in Engineering Applications of Computational Fluid Mechanics, 2018
Sina Faizollahzadeh Ardabili, Bahman Najafi, Shahaboddin Shamshirband, Behrouz Minaei Bidgoli, Ravinesh Chand Deo, Kwok-wing Chau
In terms of existing studies, the work by Cong et al. (2016) has developed a reaction mechanism for the H2S thermolysis process. A reaction path analysis is applied to determine the reactions that were responsible for the formation of H2 and S2 from the hydrogen sulfide. Yeheskel and Epstein (2011) developed a volumetric reactor in order to produce hydrogen through a solar thermolysis of methane in the presence of carbon particles cloud, which were a priory seeded or chemically produced. Naterer et al. (2015) developed a new solubility model for CuCl–CuCl2–HCl–H2O quaternary system where a new integrated process for-electrochemical hydrogen production was used to increase the speed and efficiency of electrolysis. Nakamura, Miyaoka, Ichikawa, and Kojima (2013) employed the thermochemical water splitting process using lithium redox reactions below 800 °C for the production of hydrogen while Ferrandon et al. (2010) investigated the hydrogen production prospects in a Cu–Cl thermochemical cycle to study the key steps of hydrolysis of CuCl2 into Cu2OCl2 and HCl in the thermochemical Cu–Cl cycle. Sahraei, Larachi, Abatzoglou, and Iliuta (2017) studied the hydrogen production using Ni-UGS as a catalyst (which was prepared from metallurgical residues by the impregnation of Ni in a solid state) through a glycerol steam reforming (GSR) process and Wang, Fan, and Wang (2016) studied hydrogen production through chemical looping reforming process by using the reactivity of NiMn2O4, employing bioethanol as a renewable liquid fuel. In this process, CO was also generated, along with H2 as a major product.