Thermal physical applications of carbon dioxide: Recent progress, challenges and perspective

Carbon dioxide (CO₂) is one of the main factors contributing to the greenhouse effect. The dependence on fossil fuels has led to increasing levels of carbon dioxide in the atmosphere every year. And it is far from enough to solve the climate problem by reducing the consumption of fossil fuels to cut down carbon dioxide emissions. In recent years, a series of researches on Carbon Capture, Utilization and Storage (CCUS) have been carried out in various countries around the world. CO₂ is a nontoxic, tasteless and stable gas at normal temperature. However, when it reaches supercritical state after rising temperature and pressure, it has the characteristics of low viscosity, high diffusivity and high density, and is widely used in green, pollution-free and efficient development technology. Because of these unique properties, supercritical carbon dioxide (sCO₂) has attracted more and more attention from researchers. sCO₂ has been widely used in many aspects by virtue of its high solubility and easy compression. Different from previous reviews which only introduced the application of sCO₂ property, this paper introduces the current research status of the application of the thermodynamic property of carbon dioxide in extraction, dyeing, pharmaceutical, power generation, heat transfer and exploitation of unconventional oil and gas, and mainly analyzes each application in detail from the aspects of working mechanism and improving working efficiency. Finally, the research direction and problems needed to be solved for the application of CO₂ thermal physics are proposed, which pave the way for other new applications.