• Journal of Hydrogen and New Energy
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• v.13 no.3
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• pp.204-213
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• 2002

In this work, hydrogen production by a 2-step water-spritting thermochemical cycle based on metal oxides redox pairs was investigated on the bases of the thermodynamics and technical feasibility. Also, a 2nd-law analysis performed on the closed cyclic process indicates a maximum exergy conversion efficiency of 7.1% when using a solar cavity-receiver operated at 2300K and air/Fe3O4 molar ratio = 10.

• Journal of Hydrogen and New Energy
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• v.35 no.3
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• pp.249-256
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• 2024

The cement industry emits a large amount of greenhouse gases compared to other industries, with about 60% of CO₂ emissions from the decarbonation of limestone and about 40% from the combustion of fossil fuels. Therefore, the cement industry needs to reduce greenhouse gases through carbon capture, utilization, and storage technology. Capturing CO₂ and synthesizing it into methanol is feasible and also useful as raw material for the chemical industry and as marine fuel. In this study, We aimed to produce methanol from syngas produced by capturing CO₂ emissions. Process simulations were performed under various conditions such as syngas ratio, temperature, and pressure for the production of synthesis gas and methanol, and the results showed that the optimal amount of methanol production at a synthesis gas ratio of 2.03.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.402-410
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• 2012

A two-loop Rankine cycle for engine waste heat recovery of gasoline vehicle has been investigated. Water-steam cycle as a high-temperature (HT) loop for exhaust gas heat recovery and R-134a cycle as a low-temperature (LT) loop for both heat recovery of the engine coolant and the residual heat from the HT loop were considered. Energy and exergy analysis was performed to investigate the performance of the system. Because two volumetric expanders are used for the HT and LT loop, the sizes of two expanders are very important for the optimization of the system. The effects of pressure ratio of the HT loop, considering the size of the HT expander, and the condensation temperature of LT loop on the performance of the system at a target engine condition were investigated. This study shows that about 20% of additional power from the engine waste heat recovery can be obtained at the target engine condition.