High-pressure delivery system for ultra high purity liquid carbon dioxide

In a process for delivering high pressure liquid carbon dioxide to a point of use at elevated pressure which comprises introducing carbon dioxide to a solidification vessel at process pressure and temperature, at least partially solidifying carbon dioxide in a solidification vessel, isochorically heating the solid phase carbon dioxide in said solidification vessel thereby increasing the pressure in the solidification vessel, withdrawing high pressure liquid carbon dioxide from said solidification vessel and delivering the high pressure liquid carbon dioxide to said point of use, the improvement for effecting recovery of spent carbon dioxide from said point of use and integrating recovery with the regeneration step of at least partially solidifying said carbon dioxide in said solidification vessel which comprises:

• withdrawing and vaporizing liquid carbon dioxide from said solidification vessel under conditions for at least partially solidifying carbon dioxide in said solidification vessel;
• combining the resulting withdrawn and expanded carbon dioxide from said solidification vessel with the spent gas from said point of use forming a combined carbon dioxide stream;
• compressing the combined carbon dioxide gas stream to process pressure;
• removing impurities contained in the spent carbon dioxide;
• and,
• introducing the resulting compressed gas to the process upstream of the solidification vessel.