A solar thermochemical polygeneration system integrated with methane

High-temperature solar thermochemical cycling is a way of splitting H₂O and CO₂ to obtain H₂ and CO. Methane reforming and partial oxidation reactions occur when methane is added downstream and methanol-power polygeneration system is established, where waste heat and unreacted gas are utilized. Three schemes are conceptually proposed, the energy consumption and efficiency of which are discussed. The results show that, water gas shift reaction and the separation unit of CO₂ can be eliminated for co-splitting of H₂O and CO₂ polygeneration system, which can obtain a solar-to-methanol efficiency of 30.52% and the net solar energy and methane consumption for methanol production of which are 65.25 GJ/t and 25.74 GJ/t, respectively. The polygeneration system integrated with methane can eliminate high-temperature heat exchanger and the self-needed power plant for methanol synthesis. The efficiency of the third scheme for producing methanol is two times higher than a solar-only system withtwo-temperature thermochemicalcycling.