(211h) An Investigation into the Effects of Impurities in Captured CO2 stream on Safety and Environmental Indicators within Transportation Pipeline and Downstream Storage

The realms of carbon dioxide pipeline transportation and its subsequent storage have long been stirring many incentives for multidisciplinary research across the world. However, there are several aspects of these processes yet to be explored in detail. Amongst these, the coexistence of certain impurities in transportation pipeline and/or storage facilities along with carbon dioxide is of utmost significance.

In our previous works we defined the indices corresponding to the safe operation of transport and storage processes with regard to the concentration of specific impurities (factors). Along with these impurities, three safety indices (responses) were considered i.e. pipeline corrosion, acute and chronic toxicities. However, these studies were focused on the effects of individual impurities alone and lacked any actual combined effects beyond additive ones. Therefore, little has been established on how these so-called impurities would affect these indices when present simultaneously within such processes.

In this study, the interaction effects of several impurities including water, oxygen, NO₂,SO₂,Cl and several heavy metals (i.e. Pb, Hg, Cd and As) on the above safety indices have been investigated in order to define the resulting safe operational envelopes. The interactions were revealed by initially developing a full factorial DoE framework and then implementing an additive approach to represent the combined indices in each run. These interaction were next amalgamated in order to produce the corresponding 3D and contour plots which highlight the boundaries between the safe and unsafe operating conditions.

This study sheds further light on how the combined effects of various impurities present in the captured CO₂ stream would affect the transportation as well as the downstream infrastructures. This is expected to potentially bring about complementary considerations. A further study to bridge between the identified safe operating conditions and the capture cost is now under investigation. This would aim to successfully provide the decision makers and engineers with a better understanding of the associated costs linked to the required safety considerations as well as the underlying trade-offs.