Process and Apparatus for the Liquefaction of Carbon Dioxide

A process for the production from a feed gas which comprises carbon dioxide of liquid carbon dioxide at a desired temperature and pressure which temperature is below ambient, above the triple point temperature for carbon dioxide and below the critical point temperature for carbon dioxide and which pressure is above ambient, above the triple point pressure for carbon dioxide and below the critical point pressure for carbon dioxide, said process comprising:

• feeding said feed gas into the entry port of a liquefaction apparatus having a flow path from said entry port to an exit port connected to an expansion chamber;
• flowing said gas as a fluid along the flow path through said apparatus and subjecting said fluid to a plurality of compression and cooling cycles whereby to generate liquid or super-critical carbon dioxide having a temperature and pressure above said desired temperature and pressure;
• passing said liquid or super-critical carbon dioxide through said exit port into said expansion chamber whereby to generate in said chamber gaseous carbon dioxide and liquid carbon dioxide at said desired temperature and pressure;
• and recycling said gaseous carbon dioxide into fluid flowing through a said compression and cooling cycle;
• and optionally withdrawing said liquid carbon dioxide at said desired temperature and pressure from said expansion chamber.