Supercritical carbon dioxide (sCO2) is nothing new, in fact an example of its application dates back to the 1980s with enhanced oil recovery from mature oilfields. But it’s fair to say that sCO2 has been enjoying something of a renaissance in recent years, as its unique properties have come to prominence in a range of once tired, less efficient or less than environmentally friendly applications.
While often derided in mainstream media in the past for its harmful environmental impact, carbon dioxide is known to be a key product across a wide range of industries – from beverage carbonation to food chilling and freezing and even the medical sector – due to its invaluable properties. Supercritical CO2 takes those characteristics to a whole new level. The very nature of supercritical CO2 means that it can adopt properties midway between a gas and liquid state and, therefore, unlock additional gains in efficiency and stability. So what is sCO2 and where is it so in vogue?
Critical point
Put simply, sCO2 is carbon dioxide in a fluid state held at or above its critical temperature and critical pressure. This relates to the field of thermodynamics, whereby the critical point or ‘critical state’ is the end point of the pressure-temperature curve that designates the conditions under which a liquid and its vapour can co-exist – and where the ‘phase’ boundaries are no longer relevant. This is the point at which the typical properties of an element as we know them are different.
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