CARDICE

During CO₂ ship transport from capture to injection sites, CO₂ leakage can occur at onshore storage vessels, from the ship vessels, and during CO₂ transfer between onshore and ship vessels. CO₂ leaks may lead to dry ice formation in the vessels and in the piping system, including the transfer hoses. When this happens, long shutdown times are expected due to the duration needed for dry ice to
sublimate before restart of transport and injection operations.

In order to model and quantify the consequences of CO₂ leakage, process simulation tools need to be validated with suitable experimental data. Blowdown of vessels filled with hydrocarbon fluids can accurately be simulated with standard process software, as there is no solid formation, and available models have been validated with oil and gas field data over many decades. However, the use of more advanced thermodynamic models that take into account solid CO₂ formation are required to simulate depressurization of vessels containing pure CO₂ or CO₂rich fluids. The validation of these complex models require comprehensive and reliable experimental measurements. However, for the time being, very few and poorly documented experimental data exist in the literature.

What was the project objective:
The main objectives of the CARDICE (CARbon Dioxide ICE) Joint Industry Project were to perform CO₂ blowdown experiments from different initial conditions and use the experimental results to benchmark and improve the VessFire process software. VessFire, developed by Petrell, is a hybrid 0D3D tool based on fluid dynamics modelling and a finiteelement method for the heat transfer within
the walls. Vessfire can handle nonequilibrium thermodynamics of vapour, liquid and solid phases, including the phase changes. However, it had not been validated for CO₂ blowdown operations.

Blowdown experiments:
o Phase 1: An extensive review of appropriate measurement techniques was done and compiled in a report.
o Phase 2: Based on the outcome of Phase 1, the necessary upgrades were done on the test setup.

Tests 1 and 2 from the matrix above were carried out to validate the new setup.
These were documented in the Phase 2 report.
o Phase 3: Some modifications were needed for the initial conditions shown in the test matrix above. Tests 3 to 10 were carried out successfully and all the results were provided in Excel files as well as in the final report.

Vessfire work progress:
o An initial report was issued with the simulation of a hypothetical Test 5 to illustrate what should be expected from the experiments in general.
o Petrell has been working on improvement of various functionalities of Vessfire throughout the project (e.g performance improvement, robustness, GUI revision etc.)as requested in the initial scopeofwork.
The final Vessfire version to be issued this year (2020) is going to include all the updates.

o Petrell has simulated all the tests and compared the simulations with experimental data. This work is documented in a final report submitted to Total and Equinor for review.

Inkind work from Total and Equinor
o Both Total and Equinor have contributed to the project by giving input to the experimental work, testing Vessfire, assessing Vessfire development work, and reviewing the various reports from Ineris & Petrell. The hours put in as inkind by both Total and Equinor have been documented and will be included in the final report of the project.

What has the project achieved/ Did the project achieve its objective:
Through the CARDICE project, a set of CO₂ blowdown tests have been performed successfully and documented. These pilot scale tests are very unique and provide very valuable data for validating Vessfire and potentially other process software tools & models.