Engineering Solutions for CO2 Conversion. Группа авторов

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Engineering Solutions for CO2 Conversion - Группа авторов


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the production of alkanes or paraffins (see Eq. (3.12)), alkenes or olefins (Eq. (3.13)), and alcohols (Eq. (1.14)) [114].

      (3.14)n upper C upper O plus 2 n normal upper H 2 right-arrow normal upper C Subscript n Baseline normal upper H Subscript 2 n plus 1 Baseline upper O upper H plus left-parenthesis n minus 1 right-parenthesis normal upper H 2 normal upper O

      Apart from the reactions described above, some undesired reactions might also occur in the process as WGSR, carbonaceous materials, Boudouard reaction, and bulk carbide formation.

      The synthesis of methanol and methane can also be derived from the syngas [115]. Methanation and methanol can be performed directly from the syngas or by CO2 hydrogenation. The main reactions for both syntheses are described below. For both processes, WGSR plays an important role and affects the selectivity to the final products.

      Power to methane.

      1 (a) CO2 + 4H2 → CH4 + 2H2O

      2 (b) CO + 3H2 → CH4 + H2O

      3 (c) CO + H2O → CO2 + H2

      Power to methanol.

      1 (a) CO2 + 3H2 → CH3OH + H2O

      2 (b) CO + 2H2 → CH3OH

      3 (c) CO + H2O → CO2 + H2

      The important role of electrolysis as a bridge between renewable energies, energy storage technology, and value‐added products (chemicals, fuels, etc.) is therefore obvious. The combination in the same step of both technologies, CO2 co‐electrolysis to produce syngas and the production of hydrocarbons by Fischer–Tropsch process, will give rise to a more efficient, compact, and environmental friendly technology. The eCOCO2 project [120] (sponsored by the EU commission via the H2020 program) based on CO2 conversion focuses on the development of co‐ionic electrochemical cells, which enable both: the electrolysis of water and the hydrocarbon synthesis in the same step. The CO2 converter consists of electrochemical cell constructed with a co‐ionic electrolyte that allows the injection of protons to the reaction cell, and the simultaneous extraction of oxygen ions. In addition, a multifunctional catalyst will be integrated in the electrochemical cell for the hydrocarbon generation. The final objective of this project is the production of more than 250 g of jet fuel per day.

      3.5.3 Other Applications

      3.5.3.1 Methane Steam Reforming

      The feasibility of performing SMR using the proton‐conducting material BaZr0.7Ce0.2Y0.1O2.9 (BZCY72) was successfully examined at low temperatures (450–650 °C) under atmospheric pressure by M. Stoukides and coworkers [121]. The system exhibited strong dependence on gas concentration, temperature, and applied voltage, as well as excellent chemical stability.

Schematic illustration of the (a) Representation of the four chemical steps. (b) Protonic membrane reformer.

      Source: Malerød‐Fjeld et al. [122].

Schematic illustration of the Co-ionic catalytic membrane reactor.

      Source: Morejudo et al. [125].

      3.5.3.2 Methane Dehydroaromatization

      In this case, methane is converted to benzene and hydrogen using a Mo/H‐MCM‐22 catalyst. Protons are transported to the sweep side, whereas oxide ions are transported to the reaction chamber and react with H2 to form water that will subsequently react with coke to form CO and H2, enhancing catalyst stability. The authors observed that the electrochemically driven simultaneous extraction and injection of proton and oxide ions, respectively, allows obtaining high aromatic yields while drastically reducing the catalyst deactivation rate by coking.

      Membrane technologies are striking as strong candidates to tackle climate change by presenting potential and effective solutions for capturing


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