New kind of catalysts for low temperature water thermolysis.
A cost of primary energy of Solar and Wind in the order of magnitude can be cheapened too by reducing their frontal dimension down to about 1.0 m2 unit, so such units are thinner proportionally and is negligible vs. a cost of electric generators being a lion's share per kilowatt, and per kWh.
(1) Al2O3 + 3 H2O = 2 Al(OH)3, heating and pressure 10 - 100 bars. 2 Al(OH)3 + k * (H2O = H2 + 0.5 O2) + Al2O3 + 3 H2O. All reagents are circular here, so they are practically free. Total energy consume is energy for the water thermolysis only, and at k = 1, being a heat of 242 kJ/mol H2 at T = > (150 + k * 242) / (450 + k * 54) = 500 C. vs. 2500 C conventional. Because renewable energy of solar and wind can be cheapened in order of magnitude down to USD 0.004 / kWh or less [1], H2 product can be 242 kJ * 10^6 * 0.004 /3600 sec./2 = USD 133 /ton H2,
(2) Catalyst: CO2 + H2 = HCOOH - formic acid. Joint target reaction: HCOOH + 0.4 * (H2O = H2 + 0.5 O2) + CO2 + H2. dH = 32 + 0.4 * 242 = 128 kJ. dS = 214 + 0.4 * (131 + 102 - 180) = 234. dG = 128 - 234 * T < 0, and T > 274 C. Because all reagents here are circular and practically free, so OPEX cost of the hydrogen is about USD 70 /ton H2.
(3) Catalyst is 0.5 * N2 + 1.5 * H2 = NH3, is joined with 0.365 mol of the water splitting, it gives a heat in electricity as a by-product and 0.365 mol of H2 at T > 770 Celsius vs. conventional 2500 C. Because all reagents are circular and so practically free, the hydrogen OPEX cost is a cost of energy consumed, so a heat of (55 + 0.365 * 248) kJ = 139 kJ /0.365 = 400 kJ/mol minus a cost of the sold electricity, and with a Capex of USD 67/ 0.73 = USD 90 it is in sum about USD 170 /ton H2.
References. [1]2021 Annual Meeting. (397e) Cheap Energy is a Key to Competitive Artificial Fuels. https://www.aiche.org/conferences-events
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