Editing CO2 Shipping (section)

== System Design and Operation ==
A liquid CO₂ shipping chain typically comprises: (i) CO₂ conditioning and liquefaction at (or near) the capture site, (ii) intermediate storage and loading at a terminal, (iii) ship transport in insulated pressure tanks, and (iv) unloading, buffer storage, and onward transfer to utilisation or geological storage (often via pipeline from a receiving terminal).<ref name="IEAGHG2020">IEAGHG, ''The Status and Challenges of CO₂ Shipping Infrastructure'' (Oct 2020). </ref><ref name="ReutersNL"/>

=== CO<sub>2</sub> conditioning and liquefaction ===
Captured CO<sub>2</sub> is dried and treated to control impurities (especially water and reactive acid-formers) and is then compressed and refrigerated to a target liquid condition suitable for storage and ship loading. Liquefaction concepts may use multi-stage compression with refrigeration and/or Joule–Thomson expansion depending on the selected pressure/temperature band and integration opportunities.<ref name="IEAGHG2020"/>

=== Port/terminal intermediate storage ===
Because ship arrivals are discrete, intermediate storage is used to buffer between continuous capture and batch ship loading. Terminals commonly include:
* insulated storage tanks (sized to ship cargo parcels and scheduling),
* pumps/compressors to match ship loading conditions,
* metering and sampling for custody transfer, and
* safety systems (gas detection, ventilation, emergency shutdown, controlled venting).<ref name="IEAGHG2020"/><ref name="ReutersNL"/>

=== Ship cargo containment and handling ===
Dedicated CO<sub>2</sub> carriers generally use pressurised, insulated cargo tanks ( “Type C” pressure vessels) with refrigeration/pressure control to keep CO<sub>2</sub> in the intended liquid state and manage boil-off or heat ingress. Operating windows are selected to avoid crossing into solid formation regions and to maintain stable two-phase margins under expected weather, routing, and loading/unloading conditions.<ref name="ABSCO2Requirements"/><ref name="ZEPShipConditions">ZEP/CCSA (2022)</ref>

=== Loading/unloading operations ===
Loading is typically performed using dedicated loading arms/hoses with emergency release systems. Unloading commonly transfers LCO<sub>2</sub> to receiving tanks and then to pumps/compressors for onward transport. Some CCS concepts consider direct ship-to-offshore offloading to reduce onshore terminal infrastructure, but these place different constraints on ship design and operating pressure.<ref name="GCCSIShippingProspects"/><ref name="ZEPPTBands"/>